The title is a bit satirical. However, Buffett is reducing his Petrochina stake. When you hold a huge number of shares, you don't go and sell off everything at one go, or you'll drive the share price down (see economics 101). You sell slowly.
He's cut his holdings from 10.16% of Petrochina's tradeable shares to 9.72%. It could be that he's just trimming his stake because the shares have appreciated. His next 3-4 quarterly filings could tell us whether he is continuing to sponsor genocide.
Like I said, though, the title is satirical. He may be indirectly profiting from genocide (be receiving dividends and capital gains), but he is NOT directly sponsoring it.
In related news, one US oil firm has exploited a legal loophole to operate in Sudan; they used a subsidiary incorporated outside the US and employing all non-US persons.