Apple isn't using any crazy tax loopholes. It's pretty obvious - they have to choose a country in the EU to operate from, and they chose the one with the cheapest tax rates. It's the same as companies moving to different states to pay lower taxes.
Do you complain that a company moving from New York to Delaware is a tax cheat? It's the same thing. Ireland is sort of a state in the EU
This is incorrect. Just google "Apple, Ireland, Netherlands" and "tax structure" and it will provide you with at least a basic understanding as to how these companies operate. It's not just switching addresses.