This is a common carbrain argument

"I already pay the gas tax"

The problem is that it's false.

In a recent study, researchers Stefan Gössling, Jessica Kees, and Todd Litman calculated the social costs of driving. They found that the social cost is about 30-40% higher than what car owners are actually paying

https://www.sciencedirect.com/science/article/pii/S0921800921003943?via=ihub

That cost is paid by non-drivers.