If you wish to opt in to taxation do so. If you don't don't.
Exactly. If I don't sign a contract in which I agree to do something for someone, then I don't have to do that something for someone. Be it paying money or working for someone. You don't sign a contract, you don't owe anything!
You have grasped in this comment that what Govt's do is attempt to force you into a contract at birth. A contract with the whole state system.
The excuse is you can politically change the system, by voteing or standing. The problem with this argument is you never agreed in the first instance to the form of the system, i.e. you never voted for that. And that keeps the large majority locked out. You never voted for the Constitution nor do you.