Not necessarily. People have been stripped of citizenship if it was determined they obtained it fraudulently, that is lying on the forms or during an interview with an immigration official.
So, actually what gp is suggesting is not completely implausible.
On the other hand, making citizenships "sticky" can dissuade people from some crimes BECAUSE they're citizens.
In the war of terrorism, U.S-citizens caught fighting for Al-Qaeda/ISIS are tried for treason (potentially carrying a death penalty) while foreign fighters could be afforded the luxury of the Geneva Convention rights.
They're enjoying the luxury of our ridiculous ... softness? Good will isn't quite it, internecine political warfare for sure. The people imprisoned there were unlawful combatants, and to among other things strongly encourage lawful combat, they enjoy no protection, they can, for example, be immediately executed.
I don’t think if you were imprisoned there that you would think it was soft.
Many of those picked up were fighting for the government of Afghanistan at the time so they should have been considered lawful combatants. The whole reason they were put in Guantanamo at the time was to keep them out of the reach of the Geneva convention.
I am hardly a support of islam or any of the cranks and criminals doing acts of terror - my opposition to what was and is still being done to Guantanamo is it totally counterproductive. It is the equivalent to a take no prisoners policy in war. If you want to bolster the enemy make surrender equal death and watch while every battle becomes a fight to the last man.
So, actually what gp is suggesting is not completely implausible.