You know it's interesting....my daughter was just born 2 weeks ago so my view point on stuff like this definitely has new perspective.
I can understand the opinion of these people in that they don't want young girls to grow up with the impression that many sports, in this case motorcycle racing, is a man's world and that women are simply decorative objects used to bring in viewers and act as trophies for the male gladiators. (This is one side of the spectrum)
That said, I think it's up to me as a father to teach my little girl that she's just as capable of racing motorbikes as little Billy down the street. ... sells, and that's OK. Anyone who's trying to argue that these grid girls aren't being objectified is lying to themselves, but I'm not necessarily against it anyways. They are willingly paid actors, not slaves.
Do I want my little girl aspiring to be a grid girl? No. Do I think we need to regulate/remove grid girls? No.
I prefer to do my best to teach her that she can work hard and have her own grid girl (or boy) one day.
I guess I just support personal choice and accountability. You don't like something? Fine...doesn't mean you need to take it away from everyone else too. I prefer neutrality.