I think some less experienced dancers are intimidated by some more experienced dancers, social or competitive having nothing to do with it. "Competitive" doesn't neccesarily mean "better." I would say my husband and I are better dancers than quite a few competitive couples in the area that show up at the occasional social. And I know one other primarily social couple that is a LOT better than a lot of the competitive couples in the area.
As far as barreling down the floor, I do get annoyed with a few competitive couples mowing down the floor, because they have NO FLOORCRAFT and can't veer off their routine. That wouldn't be because I'm intimidated by them, but because I think they have things they need to work on before they get on a social floor. I'd be happy for them to have a competitive couple only social to go to, so they aren't making a mess of our floor!