The argument from asymmetry

A redated piost

From the debate with Craig: Jesseph's atheistic argument from Asymmetry
This has been a tough one for me to make sense of. I think he has in mind something like this:
1) All believers in supernatural religions accept some supernatural claims and reject others. They, for example, explain the growth of Christianity in terms of the working of the Holy Spirit, but the belief that Joseph Smith translated the tablets with divine help as the result of some kind of delusion or dishonesty.
2) However, once you accept the supernatural, there is no principled way to prefer on supernatural explanation to another.
3) Therefore, theistic religionists of all stripes reject some claims and accept others for no principled reason.
4) But one should have principled reasons for accepting some beliefs and rejecting others.
5) Therefore, you should reject theism in favor of atheism.
Questions about Premise 2
The key premise is 2. It does seem that some supernatural claims seem antecedently more plausible than others. Actions attributed to God that serve a redemptive purpose seem more probable than those that don’t serve any. There is also better or worse testimonial evidence in favor of some claims as opposed to others. So I don’t see how premise 2 can be defended.