I wouldn't assume people are "quite happy" to do anything of the sort. But there will be circumstances where people weigh everything up, analyze honestly what they are doing in the context of their own lives and conclude that it's a reasonable course to take. Just as they did
en masse over the 250W eBike issue. They won't do it
en masse with these bikes largely on account of considerable additional cost and limited supply set against the relatively limited additional benefit they get from them. So that's a self-regulating equilibrium.
All disregard is not "blatent" disregard. It is often carefully weighed up as to whether reasonable in all the circumstances. People have every right to moan when any injustice is metered out on account of unfair and unrealistic laws. No point comparing to the scooter laws - I personally think they're inappropriate too, but hey ho. There have been many laws repealed on account of being deemed inappropriate after sufficient time has passed.
There are even more which exist but are so rarely invoked in practice all but the most knowledgeable of the legal profession are unaware of their existence. Some will very likely carry potential prison terms. I'm sure enough of these could be dug up to make it hard for you to lead anything like the reasonable modern day-to-day life you are accustomed to without breaking several every day, with enough effort put in at the Law Library (but there are more productive things to do !).
The facts do not appear to support the legal position as to the dangers posed by S-Pedelecs. But the main point is there are likely better uses of public resources than to pursue riders of these bikes on the basis of a hypothetical danger. The riders have taken a risk-based approach as a result. The outcome will most likely be that S-Pedelec owners ride their bikes with no additional risk to society and everyone gets on with focusing on more important things.
And that's where I think this is all a complete red herring. E-bikes not conforming are motor vehicles and will be treated as such. Therefore a case involving a non-compliant motor vehicle that's electric is no different to a case involving a derestricted petrol moped. The argument that in some way riders of bikes not classed as bicycles will affect riders of a clearly defined group of eBikes classed as bicycles is not sufficiently convincing to warrant the attacks on riders of one by riders of the other. It's basically, to me, just paranoia and hubris. It's those recumbent riders who pose the real dangers