The old 'it's the owner, not the gun' argument..
If humans could be relied on to act courteously at all times we wouldn't need laws, period. We'd always be acting to minimise risk and maximise the enjoyment of other road and path users. Alas, until such time magically occurs regulations are there to give authorities the stick they occasionally need to whack the discourteous duffer puffers into line.
It's always a balance for legislators between the rights of the individual and the utility of the mass. The US has gone one extreme with it, Canada has found a middle ground, Australia (in adopting the UKs regulation wholesale) has gone the other extreme.
Further, I'd argue it's human nature to push the boundaries. I see it on a popular local shared pathway all the time. I've seen countless near misses (and the occasional hit) as the (unpowered) road warriors blast past pedestrians in their quest to earn a new button or whatever on Strava. They may well have all acted courteously at first. Bit by bit dangerous behaviour is justified and normalised. The end result for me is that pathway is no longer somewhere I'd take my young kids for a ride - it's too dangerous.
For the record I hate our AU 25km/h limits, but while ever they're the law I'll begrudgingly comply. (Contrary to popular belief we Australians love our laws - one upshot of which is our relatively Covid-free country.) I have written to MPs requesting a revision, but don't expect action on that front anytime soon. Anyway, philosophical digression, apologies.