Hillary Clinton went on TV and said we should get rid of Section 230 in order to moderate content. So is it really that surprising that SV made a right turn?
This argument doesn't hold water. Hillary Clinton is kind of irrelevant at this point. She doesn't hold any kind of elected office and remains pretty unpopular among lefties after losing in 2016. Meanwhile Trump openly tried to reduce the protections of Section 230 while he was president[1].
SV made the choice before (by accepting money from dictatorships for political influence via social media). Attempts at regulation were a reaction to that.
There's no way the situation can stay like that forever. There will be regulation like there's regulation of TV, radio, press, etc.
Without regulation you don't get a libertarian utopia - you just get oligarchy.