Twas a deliberate act, on the part of Jono and the X-team, for plot reasons. So, he didn't quite "get away" with anything.
That having been said, Jono is not usually remotely admirable or likeable in his interaction with girls - he's a bit of a shallow prick, actually.
I think the OP mostly likes this because of the very clear rebuttal of the supercilious "X-men are just a big, happy family" thing going on here. That's why I like it :P