Photo by Best Worst Movie
Shlomi suggests that the often-suggested method of ignoring the trolls (often referred to as "don't feed the trolls") is not the way to go. Neither is criticism, calling for banning, or asking a troll to simply stop trolling. So what should you do? Ask questions to clarify (e.g "Why do you feel that Python is so bad? What do you find wrong with it?"), and kill with kindness (e.g. "It's OK to prefer Perl, we'll still accept you here."). As frustrating as it may be to be nice to someone who isn't, sometimes people just want to be heard and accepted.
This is generally how I handle angry people and it's always worked pretty well for me. How about you?
Dealing with Internet Trolls - the Cognitive Therapy Approach [Unarmed But Still Dangerous via Hacker News]