Not all of them did. I read that after WWII, there was a national-scale gang war inside gulags between criminals who either fought as soldiers in the army or at least collaborated with the prison administration and those who remained faithful to the criminal traditions by refusing to do either thing. The authorities of course, encouraged the first category, the so-called "b@#ches", as they were labeled by the traditional thieves in law; that's why those were called the "b@#ch wars" (suchiyi voiny).