Were these Pharisees hypocrites like the whited sepulchers Jesus condemned?
No, they were not the whited sepulchers Jesus condemned. These Pharisees had embraced Jesus as Messiah and believed. They were not merely religious with nothing. However, they still insisted Gentile believers be circumcised and keep the Law to be saved, creating contention with Paul's Gospel of faith alone.
Les explains that these were believing Pharisees, not the whited sepulchers who were religious but had nothing. They had seen the light that Christ was who He said He was. Yet they said it was needful to circumcise Gentile believers, and they did not stop there: they commanded them to keep the Law, or they could not be saved. This was the bone of contention between the Jerusalem Jewish believers and the Gentile converts Paul had won in Antioch. Les notes the same demand persists today: people say they believe the Gospel, but it is not enough alone.