I think it was even worse during BB6 this year than CBB. Some people seem to decide who to support, as if it was football, as someoen said, and then almost literally hound anyone who disagrees with them and get very nasty and insulting and snide. I can't say I know why.
I hardly ever have someone I particularly want to win and then find myself getting defensive and polarised for no reason because someone (I feel) is forcing me to!
Having said that, I dislike Galloway but certainly not enough to be rude to someone else about. It is possible to disagree without getting personal.
One of the tactics I dislike the most is where you might, say, express mild disapproval of someone throwing water at another HM or something and, then, you get harangued with 'therefore that means you must support the genocide that another FM has carried out'. And, of course, not liking Galloway means you support children being blown to pieces in Iraq.