When I was at FastMail I did a lot of very manual work to not just block spammers and other abusers, but to make their life as difficult as possible. That included figuring out how to notify the people running the servers they used (including sometimes finding the IRC chat for the folks on that server and telling them they had an intruder). One of my favorite things was to redirect bounce messages that were targeted at innocent FastMail customers to the actual spammer's email address -- which I found stopped the spam from them very quickly, once their inbox filled up with thousands of bounce messages!

Personally, I think it's reasonable to care about such things, and to try to do something about it. If no-one cares or tries, then sucky people will just suck even more.