Yes, what exactly do Baha'is believe is true about Christianity?
The spiritual teachings of Jesus, that which Christians pay little attention to since that are caught up in the false Christian doctrines.
Especially about what Christianity believes about Jesus?
No, as you well know Baha'is do not believe what Christianity teaches about Jesus, the top 4 beliefs being:
1) Jesus is God
2) Jesus is the only way to God
3) Jesus rose from the dead
4) Jesus is going to return to earth
By the time Baha'is are done with them, I wouldn't call Christianity a "true" religion but a false, made-up religion.
Then you would be in agreement with George Townshend.
“As Jesus prophesied, the false prophets contrived to change the essential meaning of the Gospel so that it became quite different from that which the Bible recorded or Jesus taught. (Matt. Vii 15-23 and see pp. 11, 12.)
It has long been generally believed that Jesus Christ was a unique incarnation of God such as had never before appeared in religious history and would never appear again. This tenet made the acceptance of any later Prophet impossible to a Christian. Yet there is nothing in Christ’s own statements, as recorded in the Gospel, to support this view, and it was not generally held during His lifetime……
Another opinion which Christians universally hold about Christ is that His teaching was absolute and final. They believe that if the Truth were partly withheld from them for a time because they could not bear it, it was divulged at Pentecost in its fullness and that now nothing remains to be revealed. But there is nothing in the account of Pentecost to suggest such an interpretation and there is no one who will believe that Jesus would have named the false prophets as characteristic of His age if this warning was to be followed by an immediate release of all Truth to the Church. What the Bible shows is rather a succession of teachers—Abraham, Moses and Christ, each measuring His Revelation to the needs and maturity of His authors: Jesus, for example, changes the divorce law and says, “Moses gave you this because of the hardness of your hearts but from the beginning it was not so.” Many times He says, Ye have heard it said by them of old time . . . but I say unto you . . .”
Another universal opinion among the Christians is that Christ was the Lord of Hosts of the Old Testament. Yet the Jewish Prophets had foretold that when the Lord of Hosts came He would not find the Jews in the Holy Land, all would have been scattered among the nations and would have been living in misery and degradation for centuries; but when Jesus came Palestine was full of Jews and their expulsion did not begin until the year 70 A.D.; it may be said to have continued till the year 1844.
To confirm orthodox Christian opinion it is customary in all churches to read on Christmas morning, as if it referred to Jesus, the passage which Isaiah wrote about the Lord of Hosts (Isaiah ix 6-7).
“For unto us a child is born, unto us a son is given: and the government shall be upon his shoulder: and his name shall be called Wonderful, Counselor, The mighty God, The everlasting Father, The Prince of Peace. Of the increase of his government and peace there shall be no end, upon the throne of David, and upon his kingdom, to order it, and to establish it with judgment and with justice from henceforth even forever. The zeal of the Lord of hosts will perform this.”
Yet the descriptive titles given do not belong exclusively to Christ, while some of them He specifically repudiated as if to make such a mistaken reference to Himself impossible. He disclaimed being the Mighty God when He called Himself “the Son of God;” John v 18-47 where Jesus repudiates the charge that He claimed equality with God, disclaimed being the Father when He said, “my Father is greater than I;” (John xviii 36) and being the Prince of Peace when He said, “I came not to send peace, but a sword.” He disclaimed bearing the government upon His shoulder or that it would be His judgment and justice forever when He said, “My kingdom is not of this world.” (John xviii 36).
Many of these false interpretations involve repudiation of the Word of God in favor of the word of man. This impious act is so craftily performed, with such an air of humility, that it might escape the notice of the most sincere and devout of worshippers. Probably few churchgoers realize today that the Gospel of Christ as known to the few in the pulpit is wholly different from the Gospel which Christ preached in Galilee as recorded in the Bible.
In spite of Christ’s promise of further revelation of Truth, through the Comforter, through His own return, through the Spirit of Truth, the Christian Church regards His revelation as final, and itself as the sole trustee of true religion. There is no room for the Supreme Redeemer of the Bible to bring in great changes for the establishment of the Kingdom of God. In fact this Kingdom is often described as a world-wide Church.
Having thus closed God’s Covenant with the Bible, sacred history—God-directed—came to an end, and secular history, having no sense of divine destiny nor unity, began.
Jesus’ revelation was purely spiritual. He taught that “My kingdom is not of this world” and that the “Kingdom of heaven is within you.”
His great gift to man was the knowledge of eternal life. He told men that they might be physically in perfect health and yet spiritually sick or even dead. But this was a difficult truth to communicate and Jesus had to help men to realize it. He would say that He was a spiritual physician and that men whom He cured of a spiritual disability were cured of blindness, deafness, lameness, leprosy and so on. This was the real meaning of His remark at the end of a discourse, “He that hath ears to hear, let him hear.” For a hearer might hear the physical word of Jesus and yet fail to comprehend the spiritual meaning. Jesus, in other words, was forever trying to heal spiritual infirmities. He thus would be understood by His disciples as a healer of spiritual ailments but by others He might be taken as relieving physical ills only.
Doubtless Jesus could, and often did, heal bodily ills by spiritual means, but this was nothing to do with His real work as a Redeemer. On the other handthese spiritual cures which he effected might be misinterpreted as physical miracles, and so were little stressed by Him. (“See that no man know it.) Matt ix 30.
Christ’s spiritual mission was, at an early date, materialized, specifically in regard to such things as the miracles, curing the blind and deaf, raising the dead. Even His own resurrection was made physical, missing the point entirely. Moreover, none of the complex order, of the ceremonies, rituals and litanies of the Church can be attributed to Christ. All are man-made, by inference or invention.
Well might Christ warn His followers that false prophets would arise and misinterpret His teachings so as to delude even the most earnest and intelligent of His believers: from early times Christians have disputed about Christian truth in councils, in sects, in wars.
To sum up, if Christians say “our acts may be wrong,” they say truly. If they say “however our Gospel is right” they are quite wrong. The false prophets have corrupted the Gospel as successfully as they have the deeds and lives of Christian people.”
The Kingdom of God, as foretold in the Bible, has come and Bahá'u'lláh is the Return of Christ.
bahai-library.com
But then they have quotes that say things like the "immaculacy" of Mary? And the "primacy" of Peter"? Which Baha'is go around saying that? For me, that makes it worse. It's like they are trying to pretend they believe in Christianity.
That is just how you imagine Baha'is think, like we are trying to 'pretend' we believe in all of Christianity to fool people, just because we share some Christian beliefs.
We believe what the three central figures of the Baha'i Faith wrote, period. We are not 'pretending' to believe in anything else.