Rubber bullets are sold under the legal pretext that they’re acceptable to use in this fashion, while the manufacturer and the police department and probably every lawyer and judge in the country knows they’re just going to shoot at people.

That is for 37mm foam that splits on the ground to spread at the crowd, they are primarily using 40mm foam rounds with a metal core, if you bounce it off the ground it can rotate and impact with the hard plastic backing, which is likely how the UK journalist who required calf surgery was injured. It's specifically recommended not to bounce them but to aim near the naval, arms or legs.

There are so many different kinds of "less-lethal" kinetics and most modern ones aren't bounced off the ground.

Steel body armor has one use these days. Ceramic plates would break upon being shot with one of these, steel will not.