I'm starting to have sympathy for how hard it is to be ecumenical in the Evangelical community. People get savaged by their brethren for simply suggesting that there might logically be a third position that still entails rejection of Catholicism, but does not involve hanging the more lurid labels on Catholicism (e.g., Judaizer). The problem is, I think, that there is not enough critical thinking about one's own position, because being critical of one's own position is viewed as tantamount to being critical of the Gospel itself. There isn't that distinction between one's position and the arguments for one's position, which leads to bad arguments being maintained far longer than their shelf-life.
I'll pick on James White, who offered a rebuttal to Paul Owen's exegesis of Galatians.
The Judaizers were legalists, who thought that the Law, which was in place long before Christ died on the cross, was sufficient for justification (Gal. 3:21). They did not need Christ to deliver them from the curse of the Law, to provide a righteousness they could not secure for themselves (Gal. 3:10-14). Why? Because they thought it WAS possible to adequately obey the Law. They did not believe that the Law brought only a curse from which they needed to be delivered by a Law-endingatonement for sin and a new covenant. That was the whole problem. The Judaizers did not see the Law as an ineffective solution to sin. That is why Paul accuses them of rejecting the need for Jesus' atoning death (Gal. 2:21). The problem with receiving circumcision was not that it added one little, itsy bitsy, teeny weeny work of merit to faith in Jesus. The problem with circumcision is that its continuation implied the continued use of the Law for righteousness (Gal. 5:3 cf. Rom. 10:4). The gospel of Christ is the negation of every effort to secure or maintain ones righteous status before God on the basis of personal obedience to the Law.
White calls this "bad argumentation," and argues as follows. First he quotes Galatians 2:20-21:
I have been crucified with Christ; and it is no longer I who live, but Christ lives in me; and the [life] which I now live in the flesh I live by faith in the Son of God, who loved me and gave Himself up for me. I do not nullify the grace of God, for if righteousness [comes] through the Law, then Christ died needlessly.
Then White argues:
Now, if this point on Paul's part is going to accomplish anything, it would have to contain a conclusion that demonstrates the error of the Judaizers, just like in our example above. I mean, if Paul's conclusion is nothing more than what his opponents are already saying, where is the force of the argument? So obviously, the Judaizers were not saying Christ died needlessly, for if they were, Pauls argument is worthless. Instead, as sober scholars have known all along, Pauls argument is based upon the recognition that Paul's opponents were not in fact denying the importance, centrality, or even salvific nature, of Christ's atonement. They, like all who have followed in their footsteps since then, recognized the necessity of that sacrifice; but, they likewise sought to control the access to that work through human means. They claimed to be preaching the gospel, did they not? Gal. 1:6-9 shows they were, of course. So are we to believe that Paul would call a cross-less message another gospel in any sense at all? Why did Paul say to those who would be circumcised "Christ will be of no benefit to you" (5:2) if his opponents were not making room for Christ in addition to their legalism? And why say, "And I testify again to every man who receives circumcision, that he is under obligation to keep the whole law" (5:3) if once again this is doing nothing more than simply repeating the very position of his opponents, who would then say, "Hey, we think Paul is starting to get the point!" If your opponents are saying you can be made righteous by keeping the entire law, it is a pretty lame argument to simply repeat their own position as if this refutes them.
This is, obviously, a terrible argument, because it excludes the rather obvious case of the Judaizers thinking that the benefit of Christ was exactly allowing them to keep the law unto righteousness, a benefit that non-Christians did not have. Supposing that the Judaizers believed that non-Christians could not keep the law unto righteousness but Christians could, imagine what a damning declaration Galatians 5:1-4 becomes:
 For freedom Christ has set us free; stand fast therefore, and do not submit again to a yoke of slavery.
 Now I, Paul, say to you that if you receive circumcision, Christ will be of no advantage to you.
 I testify again to every man who receives circumcision that he is bound to keep the whole law.
 You are severed from Christ, you who would be justified by the law; you have fallen away from grace.
Thus, St. Paul's statement in 5:3 is a dire threat in the context of 5:2 and 5:4. Far from being a repetition of the Judaizers' position, it is a rebuke of the form "If you believe being Christian means that you can fulfill the law unto righteousness, you are in exactly the same boat as the non-Christians." Or as the converse argument proceeds in Gal. 2:20-21, "If all Christ does is allow you to fulfill the law unto righteousness, you could have done that before; Christ didn't have to die for it, so you are rendering his death meaningless." So ISTM that the Judaizers clearly could have thought that Christ's death had a purpose, but the *wrong* purpose. In that light, St. Paul's response would make sense; he would be rebutting the idea that the purpose of Christ's death was to allow people to fulfill the law unto righteousness.
Now it may be that White has other reasons to disagree with this interpretation, but the argument thus far presented that Owen's interpretation would render St. Paul's rebuke meaningless is clearly false. I also question how much sense St. Paul's lesson about St. Peter compelling Gentiles to "live like Jews" (Gal. 2:11-14) would make if White's interpretation of the Judaizers based on Gal. 5:3 is accurate (i.e., that the Judaizers want to selectively keep portions of the law, but not the entire law, as a means to appropriate Christ's righteousness). My hypothetical account of the Judaizers' belief would make a coherent whole of Gal. 5:1-4 while also harmonizing with Gal. 2:11-14 and 20-21.