A little corroboration would have been nice. Like someone reading Matthew's gospel and saying "yes, I was there. I saw the dead people walking around town." Or Luke, who says he researched the events that he talks about, apparently he never interviewed Matthew and got his side of the story. Unfortunately, it makes the gospels sound like the writers added things in to spice them up. And, unfortunately, it turns some people off to the point they reject the stories as myth and legends.
Then again, look at 1 Corinthians 15:
For I delivered to you first of all that which I also received: that Christ died for our sins according to the Scriptures, 4 and that He was buried, and that He rose again the third day according to the Scriptures, 5 and that He was seen by Cephas, then by the twelve. 6 After that He was seen by over five hundred brethren at once, of whom the greater part remain to the present, but some have fallen asleep. 7 After that He was seen by James, then by all the apostles. 8 Then last of all He was seen by me also, as by one born out of due time.
Who are the 500 that Christ supposedly appeared to? We don't know. That's one oral tradition that has been lost. St. Paul just said, "Want proof of Christ's Resurrection? There's a little less than 500 people still alive that can tell you all about it, go ask them." I assume a similar thing in the Gospel of Matthew is at play; no witnesses were named, because if one had a question, one could simply go and corroborate the events of the Gospel with those who saw it, because they were still alive at the time that the Gospel was written. It was treated as a common-knowledge event.
