I can remember many decades ago an acquaintance who refused to be seen taking anything over size 10 into the changing rooms. hence her skirts never zipped up all the way.
If you are sensitive to it, it is certainly the case that some shop staff alleviate their boredome by finding ways to moack customers, and being sturdily built gives these sorts no end of entertainment. So I can understand why some women might feel intimidated and end up buying clothes too small.