Why are classic 4 door sedans "disliked"?

Extra doors equal extra weight
This was my thinking too in 1970 when I bought a 70 Swinger340/4-speed/3.55s, that tipped the scales at 3330 with me in it. Yeah it was a 2-door.

My previous, and First car had been a 57 Belaire 4-door hardtop, bought in 1969, and altho in pristine condition, it didn't survive long with me behind the wheel. I burned up the PowerGlide in no time.
It turns out that the A833 in the Swinger, also couldn't take me. During the time I owned that car, about 5 years, I rebuilt that trans twice.
I owned a lotta 2-doors until 1980, when my first baby was born. Then I owned mostly station wagons for a few years. My next 2-door came in year 1999, the year I put my Barracuda on the road, as a Second car. The wife still drove the kids around in the 4-door cars. But soon they were all graduated and had flown the nest. Altho my Hotrod was born with a fold-down rearseat, at 72 pounds, it wasn't in there much past my son's grad (2002), and I sold the entire 68 interior it just a few years later, in favor of a transplanted 69 FormulaS interior, and the rear seat is still in the rafters to this day. Eventually the 68 seats were swapped for lightweight, bolstered-seats from an RX-7, and then I moved the shifter about 7 inches back, a lil to the left, and raised up real high.I finally got control of the car, and the shifting, due to my azz staying put.
I've never missed the back seat. nor the original buckets. and so two extra doors would have been moot.
So, you might ask, what do I use the back seat for? Don't laugh but, I put a small low-sided box back there, to catch the keys which often vacate the very worn 68 ignition switch, on the one-two shift, whenever I floor it. I gotta tellya, the CenterForce Dual-Friction disc really bites. Eventually, I put the keys on a tether, cuz they didn't always land where the box was, and crawling around in the back, hunting for them, got to be an unseemly sight, as myazz got to being old, lol.