From the BBC: "In his article, Mr Johnson said full-face veils should not be banned but that it was "absolutely ridiculous" women chose to "go around looking like letter boxes"." He wasn't actually attacking women's right to wear the burka. To use your example, it's comparable to him mocking overlined lips. The difference is that Muslim women are often victimised for that choice in the UK, and his words could be seen to condone bigoted behaviour. It was inappropriate and irresponsible.
he was literally the secretary of state like last month. this is a man with power who is mocking women’s choices. do you not see how dangerous this is?
furthermore, saying that islamic traditional dress looks like letter boxes is literally mocking. would you be arguing this if he had said something comparable about another culture’s traditional dress?
it’s islamophobia pure and simple, and he’s a bigot.