“Zero safe limits” has a lot to do with the scale. While it can’t be good for those in attendance, between the relative infrequency of races, limited number of cars on the field, and general use of batteries even in the ICE leagues (let alone caring about emissions for efficiency purposes), it is probably perfectly fine. Or, more pointedly, all the OTHER emissions are likely a much bigger concern.
Also, the number of safety and societal dangers of F1 go WELL beyond just dangerous fuel. Like, I enjoy watching the occasional race. But holy shit does F1 make pro wrestling look “not THAT bad…”