The point is that crowd, taken to be representative of the Jews, is not the same as the group of disciples to which the metaphor of salt of the earth is applied.
Lets consider it. What about: [Mat 7:28 NIV] 28 "When Jesus had finished saying these things, the crowds were amazed at his teaching,"
This Mat 7:23 supports that the Jews are the salt Jesus refers to, not just Jesus disciples; because the crowds are amazed at his teaching. There are other hints. The book Matthew is addressed to Jews, begins with a geneology, accesses Jewish events that cannot be understood outside of Judaism such as Jewish weddings, is peculiar to Jewish culture. I think though that another strong indication is the twelve apostles correlate to twelve tribes and are called by Jesus the "Fishers of men." Here is a blurb from the passage about the Jews who Jesus will summon through his fishers of men:
[Jer 16:16 NIV] 16 "But now I will send for many fishermen," declares the LORD, "and they will catch them. After that I will send for many hunters, and they will hunt them down on every mountain and hill and from the crevices of the rocks.
and then it talks about their sin and finally that they will be taught his power and might ending in verse 21.
21 "Therefore I will teach them— this time I will teach them my power and might. Then they will know that my name is the LORD."
Hence the Jews are somehow necessary in Jesus conversations. Like the needed salt. His apostles are the fishers of men to bring them back to be that salt: one apostle for each tribe.
Another indication is Zechariah 14:21 In it even the bells on horses will be holy and all nations will recognize this. The Jews, again, are the ones in this figure who make a difference; hence Jesus probably thinks of the Jews as the salt. If they were not going to brought back and were to be disposed of then I would think differently.
The burden of the Pharisees was their exclusion from the kingdom of heaven.
Just an example of Jesus not relying upon language to transmit the spirit. Are you suggesting that Jesus' examples and explanations are always clear and that he doesn't expect us to receive revelation directly from the Father? If so I don't agree with that. He could explain many things. That I would agree about. It was this concept of transmission of the spirit which he did not agree about. At his baptism John B. has a vision of the spirit flying down and landing on him. Its the opposite of having the spirit infused through teaching. Also Jesus is the greater of the two, yet John B is to baptise him. This also suggests that Jesus is rejecting the discipleship methods of the time of all the major teaching groups including Sadducees and Pharisees.
No, that doctrine is from Paul eg Romans 13. Paying tribute to Caesar was conditional on what was due to Caesar (Matthew 22:17-21).
Maybe. Its not like I am stressed about being a Jew under Roman rule, because I'm in a free country. Its not a decision I need to make, but the Jews of this period do. Jesus does say things though like going twice as for for a Roman.
Why do you think that there are different types of leaven in the sense that it is used in the gospels?
It seems like a tangent not a main issue, but the Pharisees have a system of teaching. Jesus wants things done differently. Probably its comparing the Pharisee method of teaching as a leaven in the week of preparation for Pesach. It doesn't say so, and I don't see any mention of Pesach in the section. Its reasonable to think of it as leaven vs. none; but it doesn't say. Its left for us to interpret.