Honestly, who cares what people do in their games and how they want to date. It's all about preference. If (s)he wants to date someone through a freakin' game, whatever. xD The rest of us who prefer to date IRL like me, lets continue to do just that and enjoy life how we see fit (I'm a Libertarian at heart on a lot of things in life btw).
I second Red Cat as well. I know a couple of GROWN UPS who met through ACNL and, one got married IRL, and the other one... oh well I'm unsure if its good or bad...they got into a relationship although one of them already has husband and children.
The people who laughs at her/him is just short on imagination I guess. Its not silly or gross, cuz its as mentioned by NIntendo, network communication game. I see its just cute.