Also, think about the implication of just happening to have four Messianic men under a Nazrite vow when Paul wandered back into town. It means that this sort of thing was normal, that Yeshua's followers considered taking on purely voluntary vows that required strict attention to ritual purity and an expensive set of sacrifices to be perfectly fine and appropriate to their obedience to the Gospel.
As I just pointed out to annalex, the problem with post-Nicean Christianity is not that it chose to utilize the freedom given in Messiah to develop a Roman/Hellenist way of worshipping the God of Abraham, Isaac, and Jacob. It's that it refused to recognize the right of Jewish Christians to continue to worship and obey God in the manner that He Himself prescribed to our fathers--and in so doing, presented a false gospel to the Jewish people for the last 1600 years.
Shalom.
Christ predicted that the Christians will be "thrown out of synagogues" (John 16:2, several similar); do you think that His prophesy was untrue, or historically followed the Council of Nicaea? How about the stoning of St. Stephen, -- was that Nicaea's fault also? And what problem do you have, exactly, with the Christian Church deciding the form and content of Christian worship?