I don't think it's quite so bad compared to many other things, and the amount of benzene and other aromatics in gasoline is deliberately regulated to a low level due to its toxicity:

https://en.wikipedia.org/wiki/Benzene#Component_of_gasoline

There have been many automotive enthusiasts who lived past median life expectancy and died of something other than cancer, and those are people who have likely been exposed to far more other solvents than the rest of the population.