[kuramitropolis]

>What can I say that prevents you from saying something?

Any syntactially correct but illogical thing, basically. The textbook example is "have you stopped beating your wife? yes or no, asshole".

Most humans aren't very good at being rational. Undermining someone's capacity for correct reasoning and effective communication is a whole dark art - one that is fundamental to our entire social reality. Also known as "trolling", in the offline world - as "bullying", or if you want to be academical about it, "exercising soft power".

Of course, it's only considered reprehensible if an individual does it.