There were bicycles in the Netherlands before they were segregated, a lot of them. Then they were kicked off the roads to let "progress" (i.e. the car) go unimpeded. Now yeah, they sell that as bike-friendly, so sad.

You're clearly not up to date with the situation on the ground here. We're upgrading our cycle infrastructure and removing cars from city centres at the same time. Where there's no space for segregated infrastructure or in rural areas where it would not be economical, speed reductions are generally applied: 30 km/h in built-up areas, 60 km/h outside.

As for the why: car and bicycle speeds are just too different. Segregation improves life for both, and especially safety for cyclists, who will always be at a physical disadvantage in an accident.

There is one basic rule of traffic engineering: first come first served. It allows for vehicles of different speeds to share the road. Your responsibility as a driver of a vehicle is to not drive so fast that you can not possibly stop within your field of view (you are not driving a train), that is enough to share the road with bicycles, tractors, horses or whatever. Of course drivers of cars do not want to be bothered with that an want the road all for themselves, that's why you still insist in getting cyclists off the roads, at least where there is enough space to do so. The fear of cars is very convenient for this purpose.

You are stating the obvious, then drawing a conclusion that is the opposite of the logical one. I can only conclude that you are trolling.

As a cyclist who have taken the effort to ride correctly not only I have to put up with motorists who think that the road belongs to them, also with bicycle activists who think it is best for me to ride as If I were a pedestrian on wheels and that of course the road also belongs to motorists. Now I also have to put up with people on the internet who say that I am a troll because I try to explain as best as I can how me and fellow cyclists are being mistreated by almost everyone.

I am a daily fervent cyclist, but from what I'm reading I don't think I am a fellow cyclist of you.

You are probably a pedestrian on wheels then

That's far from how I would describe myself, but go ahead, thoughts are free.

Also the speed is not so different. The speed difference is even greater between bicycles and pedestrians yet you see places where they mix them. As a pedestrian I have been passed by cyclists which disappear much faster than a car when a car passes me as a cyclist.