I haven't seen anyone claim that Facebook is failing to pay all the tax they are legally obligated to pay. Did you mean something else by "everybody pays his taxes?"
There are currently investigations in the EU if FB did fullfil the requirements to use the tax loopholes they are using. If not, FB did not pay the taxes they are obligated to pay.
And if they didn't, they'll be fined and be forced to pay whatever they didn't, which will probably not happen again in the future as a way to avoid being fined.
If they did? You seem to be dancing around the central point, which is, these numbers, while absurd, are generally completely above board and legal. Nobody is going to pay more tax than they're obligated to, and it's absurd to expect otherwise.
Thats actually not the case. Starbucks voluntarily paid tax in the UK, even though it was apparently not obliged to as it has never managed to make any money(!).
The problem about prosecuting these cases is that transfer pricing and IP "costs" are difficult to demonstrate as faked, and some of the loopholes may be legal, although Apple is now dismantling its double Irish Dutch sandwich, one of the tax avoidance strategies it invented.
"Investigations in the EU" means jack shit. There have also been "investigations in the EU" about whether Google is an illegal monopoly and whether Facebook needs to segregate all its data on European entities into separate European data centers.
From the perspective of someone who sees the options of "fuck your own population over and kill all healthcare, welfare, etc" or "force companies to pay their taxes, and maybe lose some features like Germany has almost no Google services available", I’m pretty happy with the choice of free healthcare, college, etc vs. having access to Google Wallet