Well, they are a major source of smog in some areas. They emit quite a bit of hydrocarbons(https://link.springer.com/chapter/10.1007/978-1-4612-3296-4_...).

They also kill quite a number of people every year by dropping heavy things onto their heads.

Grandparent poster is quite likely a loon, but hey, no reason we can't use it as a starting point to discuss things.