The SEC exists. As do many other mechanisms by which the government regulates direct and brokered securities trades and sales. You can make the case that some of those controls are poorly/ineffectively implemented, but you can’t claim that it’s not something the government routinely regulates, intervenes in, and sometimes prohibits outright.

It's harder for private companies sure, but who will stand in the way of govts if they said we will sanction your if you buy X or Y company?

This entire argument doesn't really hold IMHO

Because the building is standing right where it is, in the open, lit by the sun every day. If you don't pay your tax, the government can just take it.

This compensates for the several philosophical and moral problems with it, and I've seen several economists declare it the best form of taxation there is.