And all the parts are freely available to build your own. No amount of legislation will stop the reckless or those with criminal intent
Quite true. But the parts have been freely available for a long time. But it takes some knowledge to put them together and make the result work well.
Now there are complete, working models on sale, available to all and sundry with no expertise or knowledge whatsoever, and that's why the danger exists.
I detect in some posts the world-weary "'twas ever thus, what can we do, can't stop progress" approach.
That will last until there is a major accident in the USA caused by an unregulated drone, exactly as TWA 800 finally woke the industry into action to remove a danger everyone knew about, which had caused many fuel tank explosions before the one in TWA 800.
Even a drone-related accident in Europe might wake up the industry. Who knows.
When it happens, prevention will suddenly become do-able. What a pity we can never learn the lessons of the past and act to prevent the tragedy before it happens.