This is of course extremely dangerous, potentially lethal.
By firing at such a high arc the canister will have a high impact force when landing and if it hits a person's head that would potentially be fatal.
As it is also very clearly not aimed and they do generate a lot of heat while active, if hitting and penetrating someone's window or balcony door instead, that could likely set fire to the apartment or more.
The instruction as designed, in general as I have been told, is that the canisters are supposed to be aimed downwards at such an angle that they impact the ground and bounce close to the ones being targeted, so that they will reach where intended but have drastically decreased kinetic energy when they may inadvertently impact some human and then probably only in less lethal legs area.
Some do instead aim e.g. directly at people's heads, leading to loss of eyes, concussions, brain hemorrhages and in some cases deaths.
Of course personally, my opinion is that everyone involved in making such should be shunned from decent society until they've demonstrated not being a threat to humanity anymore.