Someone makes a topic about getting fed up with jackasses...

Option 3.

Sarcasm probably.

3 is the only way I reply to 90% of topics

Depends entirely on how they define "jackass", and why they're fed up.

If their complaints seem valid, I'll be empathetic.

But if they come across in a way where it seems that the only real jackass is them, and that they're getting upset over something phenomenally stupid and/or pointless, I'll probably begin shitting on them for it.

On the Internet, the latter occurs far more frequently than the former.

Yeah honestly it varies. My responses vary on a case-by-case basis. If the TC is complaining about something that I also find to be annoying or inconveniencing, then I'll typically agree and throw in my two cents. But if it's a stupid topic about something stupid, then I'll reply with general jackassery.