The fact that Reddit makes it impossible for its users to change their usernames is both cruel and hilarious. It's fun to think about how all the teenaged trolls in 2005 who chose crass usernames for a laugh are now thirty-somethings making heartfelt points about serious issues from accounts called “I_Like_Boobies_69” and “StinkyButthole420." There are so many examples of funny times the username didn't check out that there's a whole subreddit called r/rimjob_steve dedicated to documenting thes…