there are AIRCRAFT OWNERS signing up to wingly
Sure: I am an aircraft owner and used to offer flights on Skyüber. All I can say is that I never saw the slightest indication of the problem that you describe.
Just because someone can choose to break the law by abusing one of these platforms is no reason to deny those people who want to use them legitimately. If someone does break the law by trying to run a commercial operation in the way that you suggest, the authorities should, and would, come down on them like a ton of bricks. I doubt it would take them very long to find out and do so.