Why Flake isn't exactly a moderate just different in opinions on certain issues as well as what appropriate political tone is.
Agreed. And this is part of the problem with most of the anti-Trump Republicans. Other than criticizing him verbally or in print, there just isn't that much they can do to oppose the man without betraying their own political beliefs. He'll probably get some push back on trade policy, they backed sanctions on Russia when Trump didn't want them. They'll stand up to him when they actually disagree and care about an issue. But that just won't happen very much because they largely agree with Trump on policy just not on anything else.