Were they talking about the cheesecake or the macabre element cause I feel like the cheesecake element wouldn't be that off putting in the FGC. Like, there's a lot of T&A but T&A is passé. The more standout element was the weirdness of it. People throwing their heads and spines to fight.
I actually do recall that thread. Essentially the argument was that Skullgirls was pulling from three main angles for its aesthetic (pin-up modeling, art deco, and mild body horror) which is generally more uneven and less appealing than mashing two styles together equally. Those definitely aren't the only influences in the game's art and I doubt it was the sole factor in whatever performance the game had, but I think the argument had some general merit.