The "clever quip" bit strikes me as rather telling; it's very much a case of arguments as soldiers, rather than actually trying to find the truth.
In the case where the argument is over whether a non-mainstream person, group, or position should be taken seriously, that person/group/position often has more at stake. That means they're (a) more likely to become flustered by such a statement, and (b) more likely to be judged harshly for responding in kind. However, it doesn't mean they're less likely to be correct.
It is also impermissible to point out the subtext; if you say, "are you saying you have no respect for me?", you lose. And that's true even if pointing that out would be a true statement.
As JoshuaZ points out, there is a third way, and it's much better.
In the case where the argument is over whether a non-mainstream person, group, or position should be taken seriously, that person/group/position often has more at stake. That means they're (a) more likely to become flustered by such a statement, and (b) more likely to be judged harshly for responding in kind.
For many non-mainstream issues I am associated with, (a) is false, but (b) is true. If anything, since in most every ideological issue I am extremely non mainstream, (a) is false, because I'm accustomed to much worse than a "clever quip". ...
A blog post by Alistair Roberts, as curated by Steve Sailer. (Steve's version is shorter and more targeted; the original blog post is the fourth in a series on triggering and suffers for its reliance on the particular issue.)
It seems like a very useful dichotomy, and strongly reminds me of Ask and Guess.