This fascinates me, too:
The "I don't care what you say and here is a 2,000 word email to explain why" genre is a truly bizarre one.
— Charles C. W. Cooke (@charlescwcooke) August 12, 2013
I generally handle not caring by… not caring; it’s OK to tell people that, particularly when they’re interrupting you*, but the trick then is to walk away afterward. Nobody’s forcing you to talk to an idiot, after all: the First Amendment says nothing about letting people impose a power imbalance relationship on other people.
No, not even on the other side of the Bill of Rights, in invisible ink or something.
*I interrupt people all the time myself; I just don’t take it personally when they tell me to [expletive deleted] myself. That’s a perfectly reasonable attitude to take, in and of itself. Of course, they’d be better off listening to me, but what can you do?