At some point you say "this is your tax", that doesn't mean that all other profit is money out of the public coffer. Governments do not tax all money.
No one said they did. I said all private money is money not available to the public. If Facebook bribes legislators to carve out tax loopholes for them, that money stays private, therefore it's denied to the public coffers.
Aside from any offended libertarian sensibilities, what part of that do you disagree with?
Our system is much too complicated and corruptible today. It shouldn't be so easy to effectively buy legislation, but as long as it is legal we can't really fault anyone with the means from taking advantage.
If Facebook bribes legislators in an illegal way they should be held to account, otherwise laws should be changed and legislators should be resigned in through both elections and checks and balances.
According to you, all money belonging to everyone is really tax money that has been stolen from the people.
There are some people who think like that but it's definitely an unusual approach. I'm sure you know what that form of society is called.
Like, a donation is voluntary, taxes aren't and you think that makes them theft, I get all that. If I choose not to donate my house to the state, it is literally money denied to the public coffers.
In the case of my home, the state has no expectation or entitlement to receive it. One could argue the same in the case of Facebook bribing legislators to get tax carve outs. I wouldn't (because it's very corrupt), but one could.
I don't agree with this model and would much prefer a simple tax code. But as-is, its disingenuous to say that taxes unpaid because one finds a legal way to avoid owing them is taking out of the public coffers. One can't take money that was never owed in the first place.