It's an opportunely for them to prove they're not bald faced liars, or living in a bubble if in the US, or if outside the US as so many are, to admit they in fact do not know anything above the slogan level of the topics under discussion. In the face of calumniates that reach the point of blood libel, "disagree" is far too weak a word.

There is no respectful way to point out someone is either so ignorant they have no place in a discussion or are arguing in bad faith. For the general stuff, they just have to learn a few things, like how many blacks legally own arms, and how the vast majority of gun owners are entirely cool with that. For the specialized knowledge I've been providing my own citation as well as in other discussions pointers to for example the absolutely essential to know about Anti-Federalists.

And I'll ask you this personally: do you really believe someone who claims to believe "the Satanic Church" is legally discriminated against is worth doing anything other than asking for citations, which he refuses to provide?