I've defended Apples tax practices in the past but I was mostly defending them in terms of their right to keep money overseas and not pay the repatriation tax to bring that money back to America. I'm an American citizen and I still believe that Apple is doing the right thing by not repatriating. I also believe that the 40% rate is harmful in numerous ways to American business, government, and citizens. Any American politician attacking Apple for this is utilizing the "total political crap."
With all that said, I'm aware that Apple is also being accused of not paying taxes in foreign countries on goods sold in those countries. Personally, I am pretty far removed from this issue, so I don't understand it nearly as well but if Apple is avoiding tax by claiming they sold those goods in Ireland then this needs to be resolved and I have no issue with those countries getting the tax that is rightfully owed to them. I would have a problem with it if Apple sold an iPhone in Florida and somehow managed to avoid paying the US taxes for that.
So basically US politicians need to get off Apple for not repatriating and they need to fix the broken US tax system. This isn't Apples failure, it's yours. Foreign countries, if Apple is being sly then go get them.