Honestly. Is it personal satisfaction? Do they think they're being funny? Do they think they'll gain legions of fans for making a nonsensical response to something that's completely unrelated to the discussion of one's personal appearance and/or "attractiveness?"
I love the Internet — but at times, I really hate the Internet.
Also, I'm sorry to toot my own horn — but I'm probably 1000x hotter than anything this jerkwad troll has ever put his dick inside. (Which, I'm betting, is still probably just his fleshlight.) Frumpy? Hardly. But, you know, whatever helps the trolls sleep at night, right?