Litvinenko was a muslim convert and a pro-chechen propagandist. Why people quote him as an authority is a mystery to me.
I just googled Litvinenko. He was buried in a Chechen Muslim funeral service. Probably self medicated in some thwarted terrorist plot with the polonium or it backfired on him?
Not all Muslims are made equal, actually. The proof of that is with people like the Kurds, or the Crimean Tatars, or even your average Chechen, not to mention all the various sects and interpretations of Islam. While Islam everywhere is a false religion, it's just not true that every Muslim community everywhere is out to behead people or is molesting little girls or boys. It is true, however, that the most anti-American Muslim groups in the world all tend to have close ties to Russia or else focus all their hatred on the USA and Israel, while benefiting from weapons provided to them by a government in Moscow that used to carpet bomb civilian cities in the Chechen war.