Yes, it's more similar to a forced labor slavery, than chattel slavery. The forced labor convention (which for some reason wasn't ratified by US) specifically makes exception for civic obligations and compulsory military service because they are fitting the definition.

Children in this analogy forced to go to prison too, when they reach 18 years and refuse their taxes.

It's still not much of an analogy unless you believe that, say, driving on the wrong side of the road, uninsured and without a license is somehow comparable to any form of slavery.

Am I correct that you invoke a social contract as a justification for involuntary actions?

1) You are forced into this contract without your consent.

2) You can't quit this contract with your property intact.

This conditions wouldn't be enforceable if they were between ordinary parties, especially when there is inequality of bargaining power, why do they hold between a state and a person?