It's not that, and about twinking. There are some who are in favor of low level content, and do get bored with not interacting with other players in the game world, well until they reach 70-80 plus that is.
I had to help out some guy, who seems to always come back to me because his guild and other players would not help him, he didn't get legit contact or help until he hit level 87.
Most people do not care for the bugs, Stockades and a few TBC dungeons are examples.
People just want other things to do than the traditional quest/turn in routine, a majority of lowbies, now, you can inspect them, mostly quest gear. Also if you communicate with them, mainly the lowies, you can ask them about dungeons, you'd see their responses vs those who are already level 90.
Stockades and Deadmines, despite the flaws in them, did not stop some from doing the dungeon, even though it is buggy. Other than that, dungeons trash kills offer a good amount of exp, better than killing boars all day.
I'm all for low level dungeons, if they do open it and it is buddy, so be it. Cata Scarlet Monastery, I know will run as it did during Graymane and Deepholm, if they open it, same goes for Hellfire Rampants and a few other dungeons.