citation please.
Paul was opposed to judaizers but did not treat them as others treated him.
Let's "observe" for this can be an instructive moment.
Acts 21
17 And when we were come to Jerusalem, the brethren received us gladly.
 18 And the day following Paul went in with us unto James; and all the elders were present.
 19 And when he had saluted them, he declared particularly what things God had wrought among the Gentiles by his ministry.
 20 And  when they heard it, they glorified the Lord, and said unto him, Thou  seest, brother, how many thousands of Jews there are which believe; and  they are all zealous of the law:
 21 And  they are informed of thee, that thou teachest all the Jews which are  among the Gentiles to forsake Moses, saying that they ought not to  circumcise their children, neither to walk after the customs.
 22 What is it therefore? the multitude must needs come together: for they will hear that thou art come.
 23 Do therefore this that we say to thee: We have four men which have a vow on them;
 24 Them  take, and purify thyself with them, and be at charges with them, that  they may shave their heads: and all may know that those things, whereof  they were informed concerning thee, are nothing; but that thou thyself  also walkest orderly, and keepest the law.
 25 As  touching the Gentiles which believe, we have written and concluded that  they observe no such thing, save only that they keep themselves from  things offered to idols, and from blood, and from strangled, and from  fornication.
 26 Then  Paul took the men, and the next day purifying himself with them entered  into the temple, to signify the accomplishment of the days of  purification, until that an offering should be offered for every one of  them.