U2 didn't move out of Ireland, U2 Ltd did. If any other business was in danger of a huge rise in taxes, they would have done exactly the same thing.
I think you'll find the members of U2 have not moved home.
What really annoys me is when people criticise celebrities for talking about helping Africa, accusing them of "not giving money themselves". Just because these people may be rich, doesn't mean they don't donate to charity! In fact, it's more likely that they would, having more money to spare.
If Bono makes you sick then I pity you and your overly sensitive gullet.
As for the song, yeah I like it.