Unfortunately there is no ignore function that can block you from seeing their posts. (You can block them from messaging you, but I can't find a way to make their comments not show up.) Any suggestions?
The best approach is to figure out where they live and send them anthrax or an ebola laced rabid bat.
Huh? No. I guess this may be the solution- avoid that subreddit (or at least posting in it), or reddit altogether.