Ted Kaczynski, Boston Marathon bomber Dzhokhar Tsarnaev, Sept. 11 conspirator Zacarias Moussaoui and Oklahoma City bombing accomplice Terry Nichols
Is there something that makes those individuals particularly difficult to contain?
For three of them, absent bomb-making supplies, they aren't particularly violent or difficult to keep in a locked facility. Nichols bought a mess of fertilizer and other supplies, put them in a truck, and planned how to blow it up. It's not as if he has super-strength, mad martial arts skills or the ability to bend steel with his bare hands.
Moussaoui is a standout among this collection due to his remarkably low intelligence. If you followed his trial at all, the top takeaway was how shockingly dumb this guy is.
El Chapo is a demonstrated escape risk, and could obviously compensate anyone who assists him to escape. So that makes sense.
But it is bizarre how we tend to put prisoners in Supermax not based on any characteristics of the prisoners, but simply based on their involvement, even tangential, in a particularly notorious crime.