Fake statistics just to illustrate the difference. Males 18-40 support porn at 60%, which is higher than any other demographic. HN is 60% males 18-40. With these numbers, 36% of HN is males 18-40 who support porn, and if all other demographics on HN oppose it, then those 36% are the minority.

(By the way, I have no idea what the real numbers are, and don't really care. I'm just responding to an evident confusion about what was actually said.)