Bruno's main deal is showing what terrible people make up the world of fashion and entertainment. He has one guy call Peter Jackson's looks a mini 9/11 and one guy to say Burt Reynolds should take a train to Auschwitz.
When I'm on long car trips with people I often start talking to them in the manner of a decadently gay German. I did this to my friend for about a month before I found out that Sasha Baron Cohen did this for a living.
The thing that blows my mind about people like this who take certain ideas serious to such tragic extrems is the complete absense of a sense of humour. I can't imagine being so blindly in support of something.