I'd be surprised if NYCFC fans actually have any real negative feelings towards MCFC at this point.
For starters, they've been doing really well the past season and a half. For a team still in its infancy it's already established itself as one of the country'stop sides. Not as good as the best, but good enough to make the playoffs comfortably enough, which is a big deal out there I believe. They play some of the best football, and arguably have the best attacker in the league in Villa. Plus anyone who doesn't like the Red Bulls has a team worth cheering for. Now as far as I remember people tend not to complain when things are going well like that.
But also, the MCFC influence on their team is much less prevalent than originally. We aren't sending them players like we used to, we aren't messing around like we did with Lampard and as far I'm concerned Vieira is their guy, not ours. Outside the fact they're ran in a similar fashion to us, as all CFG teams are, they are an independent side. And we at MCFC treat them as such.
I imagine the only people who dislike MCFC at this point, are those who've always held some disdain towards us (eg United fans).
Melbourne however, I'm more interested in hearing what they have to say. They aren't doing as well and I'd be keen to learn what's different there as to New York.