I guess you aren't too familiar with the context. The Chechens wars were major post-USSR wars fought by Russia, extremely bloody and violent, and an awkward point in Russia's self image as a major power. In the first Chechen war, the tiny, remote breakaway region declared, and maintained on battlefield, it's independence from Mighty Russia. The Second installment undid that, and was what you would consider the first major popularity booster for Putin - regardless of whether the FSB was bombing its own people. Either way, the stakes were high, these weren't obscure wars.

As for the "pure psychopaths" bit... Russia has a long history of sacrificing its citizens for the Greater Good. The "meat grinder" in Ukraine is one example. Another, quite unambiguous one, is the Dubrovka theatre hostage crisis: https://en.m.wikipedia.org/wiki/Moscow_theater_hostage_crisi... . Terrorists (Chechen actually, though there is speculation, again, about FSB involvement) took a whole Moscow theatre hostage. The anti terrorist units attacked, killing all 40 terrorists but also over 120 of the hostages. A combat gas was injected into the theatre, which incapacitated the terrorists and allowed an armed attack, but also killed lots of the bystanders.

As for books, I can't recommend any "latest history" books on Russia, but you could do a lot worse than "Red Notice" by Bill Browder for general context. It's a great book, about a Western (American?) guy who goes to Russia in the 90s, sets up an activist hedge fund, and makes a killing. All was well so long as he was useful to the government, but when their paths diverged, all got rather messy.