Instead of assuming the person you're chatting with is talking about slavery, and then when they clarify they're not talking about slavery, and you saying that it could be about slavery, you could just as easily say, "oh I misunderstood you". Sometimes humans have misunderstandings. Languages are messy. Just let it go.
Your agreement is irrelevant. Have you registered for selective service? Paid taxes? Have a drivers license? Check youtube for "sovcit traffic stop" to see what happens when people think they can live independent from the rest of society. The Amish must obey traffic laws just like everyone else.
>> Also I'm free to leave.
Nope. Many an american has fled to canada to avoid taxes/draft/jail. They are caught eventually. Citizenship is not property. You cannot just set it aside when you dont agree with its obligations. There is a process for leaving. It isnt short, easy, cheap or in any way guaranteed.
You're free to leave only if another country accepts you which is not a given.