So I’m aware there is a right-libertarian argument at work here that frames all taxes, always, as “stealing”. However, there’s an argument here that can be used along more democratic socialist lines.

Taxation in representative democracy is legitimate when the democracy itself lives up to the terms. We have come to some kind of consensus as a society on the level of taxation and where that money should go. When we do that, and we say the road is “our road”, we mean that in a literal way. A part of the fruits of our labor were diverted to build that road, and we get a say in how it works.

The US is not a democracy that lives up to the term. “Taxation is theft” is correct in this context.