What is Yuri Milner thinking? That’s the question I posed last week to Milner’s spokesman, after Russia launched a full-scale invasion of Ukraine, and then again on Monday, after Western governments responded with crippling sanctions. Milner, after all, is easily among Silicon Valley’s most prominent Russians, having made billions of dollars as the force behind DST Global, the venture firm that placed historic bets on Facebook and Twitter, among other Bay Area landmarks. But it was Milner’s embattled friends that put him on my mind: The Russian provenance of DST’s early capital was supplied in large part by Alisher Usmanov, a Russian oligarch who made his fortune in metal and mining before teaming up with Milner in 2008.