the "yes" is supposed to symbolize who they like, and the "no" is supposed to symbolize a person/character they hate.
also, the "grounded" thing is just little kids under 8's amusement. i don't get it either.
basically, to summarize, it's kids having hate boners for each other, and showing it by making loving complicated usernames.
(and why the forget is cailou in everything??)