HN is far more coastal-liberal than any flavor of libertarian. With a few exceptions, of course: people favor some policies relating to tech on which the conventional left doesn't have a strong opinion.
Not sure -- to me it looks like at least the majority of commenters are quite strongly pro-regulation: e.g. look at all the discussions of AirBNB vs. zoning just a few weeks ago, or 23andme more recently. Sure, voter and commenter demographics could be different, but probably not that much.