I find it bizarre that they feel the need to make the statement - it's not like there is any chance he would be considering coming here.

Speaking as European (non-UK), I do find this bizarre because it makes the UK look weak. It loses face.

You would expect the UK to have enough going for it that it can stand up to the USA, yet here they seem to be so scared of some diplomatic conflict with the US that they preemptively ban someone who is not at all a criminal (under UK/EU law). It's not something you would expect a proud nation to do.