So, those who reject the idea of taxation based on its involuntary nature and speak out against it as a violation of consent, aren't being stolen from?
No they are not. They are just being dramatic. Especially considering the untrue nature of the premises their argument stand on.
It is a trade that the people have agreed upon communally. Attempting to live there without paying taxes would be the only real theft. Leaving would be how you would avoid stealing.