Why are classic 4 door sedans "disliked"?

A friend of mine grew up in Europe and he doesn't get the whole two doors are favored over four doors in US collector car market. To him it doesn't make any sense. So its like well go spend less on a 4 door classic you like who cares.

The OP that started this thread is in Switzerland. What you wrote above aligns with his viewpoint.
I don't see 4 door cars as performance models and for all of my life, that was all that I aimed for. Americans of my age grew up with the 2 doors being the performance models and the 4 doors being aimed almost entirely toward practicality. There were no 4 door Road Runners or GTXs, no 340 4 door cars. No 440-6 4 door cars and only a scant few 4 door Hemi cars built. It wasn't just enthusiasts that followed the trend, it was the automakers building them that were a big driver of the sentiment.
Yes, times have changed. 4 door BMWs, other Euro supercars, the 300 and Charger and a few others built in the last 20 years have resulted in a shift of what is cool. I didn't see it coming but many young guys that like these cars are far more open to the idea of building a 4 door than we ever were.
Example:
I'm going to embark on a project with my 13 year old nephew to build a classic Mopar for him. He likes the 70-74 Barracuda and the Duster/Demon/Dart Sport but when I showed him a picture of a Dart 4 door, (as a joke, just to see how he'd react) I asked him what he thought. he said that he didn't care! For him, a muscle car means a classic American car with a V8 with dual exhaust.
The picture I showed him was similar to a 69 Dart that I may be getting. It is a plain Jane slant six/904 4 door that normally I would ignore.
Oddly, I have found myself drawn to the idea of having an almost completely stock looking 4 door car that rides nice, performs well and looks basic. I'm talking no vinyl top, no aluminum wheels, nothing flashy. Wheel covers, white wall tires, shiny paint, a decent stereo and that is it. Maybe a roller 318 or 5.2 Magnum with a Thermoquad and dual exhaust. Electronic ignition too. Basic, reliable and comfortable.
No, I have no intention of selling the other cars. A man can have fast cars and one comfortable cruiser at the same time.