I'm not sure it's quite as black and white as you're making out. I'd imagine that managers and directors give artists little option about how to dress and even less to others featuring in pop videos. I'd also be amazed if there aren't pop videos out there featuring people whose primary purpose was to ***illate. However the point remains that it can be argued that all of these people are there with a purpose other than to ***illate.
FWIW, I can into this pretty meh and it's still something I really can't get remotely upset about, but having read around the subject and thought it through, it all seems to come down to the word objectify. If the walk on girls and pit girls are being objectified, then I don't see how anyone could argue that their presence is a good thing. As they serve no other purpose than to ***illate, I don't see how you can argue that they're not being objectified. I wouldn't go so far as to say they're a bad enough thing that they should be banned and I'm not even sure that if I had the choice as the head of the FIA / PDC I would bother rocking the boat by getting rid of them, but as that person in charge, I'd be happier without them. In that position, I would be more bothered about the outdated image it gave my sport than the objectification of women. As a (albeit old fashioned, miserable) fan of sport, I'm not a fan of most types of razmataz and would put this in that category. I see it as detracting from the sport itself and implying that that it's not entertaining enough to stand on its own two feet.
I'd be interested to hear whether the remainers agree with my thought process and whether you're pro-remain because you don't think it's serious enough to take action on or if you disagree with my thought process, at what point.
Edit: re: your final point, I have never understand how Hooters manage to trade in the UK, although I suppose you could say the same of plenty of other businesses that manage to work their way around employment / equality laws.