Taxes are not theft, but a precondition for the constitution and intelligibility of the claim to ownership on which notions of theft depend in the first place.
Taxes are not involuntary charitable contributions, since the basic rights secured through taxation cannot be regarded as matters of charity else they are not rights in the first place.
Taxes are not, however annoying they may seem, burdens on our freedom, so much as indispensable enablers of freedom -- and hence they are a precondition for the constitution of the very experience of the "voluntary" on which notions of the involuntary depend in the first place.
Taxing more those who profit more by their personal recourse to the shared inheritance of knowledge and culture, to the shared inheritance of the limited environmental resources on which we all depend for our survival and flourishing, and to the benefits of collaboratively maintained infrastructure, institutions, norms, trust, legitimacy, and security is not unfair so much as a basic recognition of the fact of our radical inter-dependence as creative and vulnerable individuals in the world, peer to peer.
Taxes, as Oliver Wendell Holmes, Jr., famously put the point, are the price we pay for civilization. Anti-tax zealots would appear to believe that you can eat civilization and have it, too.
Taxes pay for the social administration of basic needs that ensures the scene of consent to historical developments is non-duressed by the threat of deprivation, inequity, or insecurity.
Taxes ensure sufficient equity among citizens so that the diversity also valued by democracy does not disable the shared commitment to democratic processes, the preservation of democratic institutions providing nonviolent alternatives for the resolution of disputes and the ongoing reconciliation of the diverse aspirations of the stakeholders with whom we share the world.
Taxes coupled to representation itself ("No Taxation Without Representation") ties the maintenance of government as such -- an organization invested with legitimate recourse to force with all the authoritarian dangers inhering in that state of affairs -- inextricably to the maintenance of its democratic legitimacy.