Boris Johnson foreign secretary appointment is a joke, but it’s definitely not funny

So why did the newly unelected British prime minister, Theresa May, give the job of foreign secretary to Johnson? Revenge? Incompetence?
Or does May, Britain’s very own Cruella De Vil, have a covert, black ops sense of humour that none of us has ever seen? Had she been so busy as home secretary, closing down nursery schools and domestic violence units, that we somehow missed her hilariously GSOH?