The worst thing for one of these online trolls is to gain no reaction from their target or others around. It infuriates them. It magnifies their irrelevance and feeling of unworthiness and that's why their attacks or vitriol progressively grow more disgusting; They just want a reaction and push harder to get one.
Eventually they turn inwards though, hating themselves even more for the inability to get that reaction, hating everything about themselves, and then moving on to seek a softer target. If no one, literally no one responded to them at all eventually they may seek seek help to address their mental issues, or just commit suicide. This happens a lot.
Thanks for commenting, I think it's an interesting topic and one most of us have had some exposure to. Also, funny to not that many who engage is the most severe of this sort of behaviour are often bullied in their own lives; It's like they have to pay it forward in a way to mitigate their own feelings. Quite weird.
Yes, when it comes to being bullied, there seems to be two main responses. One is to never make anyone else have to feel what you've been through and to develop more empathy and the other is to make others feel as bad as you feel. Thankfully, I think the first response is the more common response.
Sad but true...But yeah, mostly the former I think. People learn from their experience and don't project that negativity upon others. Those who subscribe to the latter are truly diabolical though and it'll end in tears...Ultimately their own.