Every company I know always avoids taxes, not only Apple...
Where did I say that only Apple avoids taxes?
The thing is, people are fed up with the way the world works. Because it works against them in a way. The public paid the costs of financial crisis: in the US, in Ireland and other countries. Meanwhile those responsible got bailouts.
The leaked Panama Papers proved that the rich get richer (companies, celebrities etc) by doing tax acrobatics. Apart from being unethical it's also unfair, because being able to pay low taxes depends on how rich you or a company is. A small, local company who would like to manufacture smartphones wouldn't have the same tax possibilities as Apple simply because they wouldn't be able to afford. The same with celebrities like Messi or Ronaldo. I simply can't afford evading taxes like they do.
And that's why "the people" are saying: enough. Because their effective tax rate is multiple times higher that those who make X times the money and who also benefit way more heavily from "public" infrastructure etc.
Back to the case in question:
No one is saying Apple should be taxed to death. They should've paid 12,5% tax in Ireland. They've paid 0,005%. And the case the EU is making is that was under a special agreement which equals "state aid" given by Ireland. And that's forbidden because it gives Apple advantage in an "equal" capitalistic market of the EU.
I'm sure that if Google, Facebook and John's Bakery had several arrangements then they will eventually be in the same situation as Apple. But now it's about Apple.