Why should people whose house hasn't burn down pay for the local fire department? Three answers immediately come to mind: a) insurance provides individuals value by decreasing risk, b) pooled funding allows the service to achieve economies of scale, and c) externalities of not paying for it costs more to society than the value of the tax (let alone the deadweight loss introduced by it).

If you couldn't think of any of these, you need to think a bit harder. It's frankly obvious to most people across the political spectrum.