In a two-party system anarchy is left wing

If we are a victim of crime then we have a choice whether or not to respond to it. If we do not respond then it is likely that the crime will be repeated. If we respond then we are defining our property rights with force and we can describe this as defensive force. When a criminal is arrested and placed in prison then the society is reacting to the aggressive crime.

This applies also in an election where we might seek to resist a party which we find to be very offensive. If we consider them (the party) criminal then to vote to oppose them might be considered to be an act of justice and law-and-order.

An anarchist views all government and all political parties as criminals since they are opposed to the concept of government. A democrat will take a similar view with regard to non-democratic political parties such as those who promote first-past-the-post. So for democrats to vote to reject fptp is an act of justice and to fail to do this is to be remiss in our peaceful obligations.

Anarchists have a preference for democracy since democracy is bad for the state so then an anarchist will seek to block first-past-the-post where possible. Because the Tory party is more closely associated with fptp than Labour then in a two-party system it is the Labour voters who are being more democratic and more anarchist. In a two-party system it is the Labour voters who are the anarchists not the Tories because Tories are more closely associated with the anti-democratic fptp voting system. The Labour party are a more recent phenomenon.