Those are opinions.
Almost everyone everywhere wants some stuff covered up at least sometimes, but opinions vary a lot as to just what and when. Despite the variance, people feel strongly about it, and think any decent person ought to see it their way.
In the France case, we've got competing group identities and some upsetting violence complicating the whole thing.
Gassor, imagine if the government said you had to let your dangly bits hang out, if you wanted to enjoy the beach. That's essentially similar to the position some Muslim women are being placed in, from their point of view.
Burkinis should be fine, and persons who don't like it enough to harass people should be arrested and given a lesson in who their enemies are, and are not. Women who aren't bothering anyone fall into the 'are not' category.