for sure these are a potential aviation hazard but let's put that into perspective; We've had tens of thousands of RC aircraft flying around, some of them quite large, for the last three or four decades with very few safety incidents.
That's true, but previously it cost a lot of money, and an awful long time to build your own RC aircraft, never mind the fair degree of skill it took to fly one.
Those that did so tended to be enthusiasts with a modicum of airsense, whereas today any numpty can get their hands on one for a few quid, and they can practically fly themselves right into the flightpath of some unsuspecting airliner.