Am I using a religious argument to delegitimize Trump? Or am I calling a evangelical who weighs in on politics a hypocrite?
We won't be worse off IMO.
My guess is that if you're honest about it, you'd like to delegitimize Graham because you dislike evangelical Christians and place blame on them for electing Trump. To that end, you'll happily use a religion-centered argument for that purpose.
And I think we'll be worse off. But I also suspect we have very differing thoughts about what should be/remain core ideals for America, so I suspect we probably disagree on a more fundamental level than simply whether or not evangelicals should be permitted to weigh in on political matters.