The argument here is "I shouldn't avoid emotionally traumatizing you because at some point, someone else in the future may emotionally traumatize you".

Perhaps there's a case to be made for exposing people to controversial or offensive ideas in a controlled environment to prepare for encountering them in an uncontrolled environment - in fact, this is frequently called a "safe space" and ridiculed by people who believe that modern societies are too "snow-flakey"!

But that's certainly not what internet trolls are doing.