But I can't because we give roads to cars for free and that can't be questioned.
For that matter I'd love to lease some of the park and ride spots near transit so I could build an apartment on them (they're nearly free) but apparently I'm not allowed to do that. I can't even use them to park a mobile home permanently. How is that fair?
But really, if roads were not free in the first place, toll roads would basically stop being a thing and the roads themselves would become the toll.
In some cases the very act of having to pay increases the utility of the road to the user - see congestion charging. This ensures people who gain the most economic benefit from using the road are the ones using this precious resource.
Of course, your point could be applied to any government-provided service where there is a fee. The tram receives public funding but I still have to buy a ticket, after all.