alt Hacker NewsCars? Airplanes? Motorcycles? Child birth? Life itself? Nothing could be done 100% safely and 100% without harm. Obsession with safety is what helps governments become totalitarian even in traditionally-democratic countries. Obsession with safety is the reason terrorists win.
Edit: Personally I think betting on war is immoral and should be condemned by all sane people, but saying that everything needs 100% safety and 100% no harm is very naive.
The items you've listed are all quite safe and palatable in their harm when contrasted with the benefits they bring. I'm not seeing the same picture when looking at polymarket - I don't see the great gain we're accomplishing as a society in exchange for an addicting platform that breeds organized crime. Some inventions are just plain dangerous and a bad idea.