First, they won't necessarily let you renounce your citizenship, if they decide they don't like your reason for doing it. More importantly, they won't allow it unless you first leave the country where you were born, which is not something anyone should be required to do, and you won't necessarily be permitted to ever return e.g. to see your family. And even if you did renounce your citizenship they'll still claim you owe them taxes, so it's a very expensive way to fail to solve the problem.

There is no "agreement". They arbitrarily and unilaterally decide that you're a citizen, and impose their rules. If you're not a citizen they still impose their rules, but with even less regard for your natural rights.