People can vote for violence

What greater good is served when we permit an action which would otherwise be considered (to be) a crime, under the protection of Democracy, when we vote to allow aggression? If the majority of people (want to) perpetrate the crime is it then absolved, for the fact of it being popular?

Is it only the number of votes which determine whether an action is aggressive?

It is not only the number of votes which determines if an action is aggressive, it is also, entirely, the nature of the action which defines the distinction. If we take taxes from someone who is selling their labour, (as in the Income Tax, or VAT) then we have initiated force as a consequence of the act of engaging in free trade, it is not because of some prior behaviour perpetrated by the victim, the taxpayer. Clearly, by the definition of the tax, it is not even making the case to be considered anything other than aggressive, there is no pretence.