One of the institutions of which our colonial cousins should be very proud is the FAA, who make all the aerospace regulations
freely available. These may seem like archaic and restrictive laws to prevent you from building your own aeroplane/rocket/drone but in fact they are extremely well researched and analysed specifications for anyone who wants to make a safe
aeroplane/rocket/drone. They are also copied pretty much verbatim by everyone except the Russians (who have a similar system but with significantly worse weather!) and us Europeans, who go to great lengths to harmonise with the FAA so that the rules are more or less equivalent
So let's get to details and look at 33.76 regarding bird strike. The rules regarding what an aircraft engine should be able to ingest are enlightening: even the largest engines are only certified safe to fly after ingesting a bird of 8lb. This is a lot less than a person (that was a ridiculous example from the GP; ingesting a person would destroy an engine). Birds are obviously a lot more easily ingested than a carbon-fibre and steel drone.
Any reasonably large drone would have enough mass to endanger a civil airliner and you're just playing the numbers until one is brought down with three to four hundred deaths.