Because the UK press is insane, Blur has been shoved down the Brits' throats for years. The Oasis vs. Blur thing hit a fever pitch backintheday, for example. It's impossible to have an objective opinion with all that going on.
I think it's easier for people (like in the US) who haven't been bombarded with this shit to simply take in the music.
Although I don't love a lot of their stuff, they are always respectable. There's a fine intelligence to their work that not many super popular bands have. I mean, the road from their limp debut to the sometimes-astonishing THINK TANK in such a short period of time is pretty remarkable.
I totally get why anyone in the UK might hate them, but I'm not sure it's Blur's fault.