This seems to be concerning but as a Dutch person who has lived in the UK for a long time the relatively recent home-grown 'fatbike' issue seems to be a much more pressing problem for Dutch road safety than this and isn't being dealt with effectively as far as I understand.

Having said that I think these American pick-ups (and large SUV's, they are part of the same problem) are a common sight here as well and should not be allowed on the road (unless maybe you can show you need one for work or business).

I see those in Sweden as well. But I also know that people are stupid. And I rather have a stupid person on a stupid bike than a stupid person in an SUV. Especially since in an accident, they will lose in any case because most are likely not street legal.