“oomis, we could say the same thing about a place open on shabbos
(and we could make an example with no chillul shabbos e.g. goy owner, workers, food cooked before shabbos etc.) “
And we have a Dunkin’ Donuts in my neighborhood that precisely fits that description AND is under the hashgocha of the Vaad of my neighborhood. Everyone agrees that the food there is 100% kosher.