When I say tax on goods, I'm referring to sales taxes which are paid at the point of sale.
And it's true that you don't have to contract to people that you don't want to, but you're thinking about it in terms of a written contract mentioning the parties, what each will do for the other by when, and bearing their signatures.
When you buy a home, you have a contract with the municipality through its purchase. You pay property taxes and they fund the garbage collection, sewers, and schools. That's the kind of contract that one has with the government when one takes an employment position; one acknowledged that the employer will deduct sums for Income Tax, EI, CPP and such and then remit that money to the government. So even though one doesn't have an express contract with the government itself, one does through the employment contract.
As well, the government is different from a biker gang. The government is, in theory at least, an expression of the electorate. It creates laws which have the backup of police too. A biker gang which is extorting someone is engaging contrary to the law. It's one of the reasons we have laws in the first place.
CRA is a creating of legislation. There's an income tax act. Some aspects of their work is likely contracted out. Plus, whoever answered the phone at their call center isn't likely the right person to ask about the legislative authority of the CRA.
I really can't debate with you about the natural vs. artificial person. That's a freeman distinction, and it's their particular philosophy.
I wish I could give you the answers you want to hear.