In as much as anyone has to respect the copyright coming from any jurisdiction they are not in. Which for the western world generally means that, yes, you do have to respect it. It being the UK and your historical reasoning isn't very relevant.

One of the main things that allows global trade to happen freely is countries cooperating such that entities from either they can enforce their copyright/patents on the other. It's bilateral, a Brit may wonder the same thing about the US or any other country and the answer would be the same.