I think it’s a form of weakness and low self-esteem.
You’re so desperate to have an impact on the world, on other people - any impact whatsoever - that if you can make people upset and hurt them then you at least register, you matter in some way. You’ve affected something.
I think it’s similarity one of the reasons why people bully others in life or troll people online - again, it gives them a sense of power, and of impact, of mattering. Doesn’t matter that it’s a negative, if it registers. Sense of power which they don’t get any other way.
That’s my theory anyway.