The difference is she hasn't mocked burqa wearers, just voiced an opinion that she has reservations over them. She hasn't said she doesn't like them because they look like bank robbing post boxes.
It's not that Johnson is pro or anti burqa, a valid debate BTW. It's the manner and wording he has...
Well I suppose it depends somewhat on the context. This is ridicule designed to denigrate, demean and divide, if not directly then at least indirectly; not just to pull someone's leg. If you want to have a sensible debate about the burqa as a supposed serious politician you don't start off by...
You can question whether a burqa is good or not.
You can't IMO ridicule, and effectively legitimise further ridicule, of whole sections of society by saying that they look like letter boxes, particularly if you want to be taken seriously, and even more particularly if you have aspirations of...