I'll probably get a warning for this, but it'll be worth it.
Because Britney doesn't make music with deep meaning to it. The British, in general, are the epitome of Eurosnobs and won't be bothered with anything that doesn't make them feel like their lives have purpose. I was much surprised by this when I went to Europe. That's why they support intellectual (Adele) and pseudo-intellectual (Beyoncé) acts because it makes them feel high and mighty. All a compensatory act, really.