Are you playing season or non-season? Non-season HC is pretty much dead, but has always been. HC is just smaller playerbase, non-season is smaller playerbase, so HC NS is pretty empty. And those who play usually don't play public games.
In general HC public games can be... difficult. I actually did a public HC (season) bounty run on TX or so last season and 2 people ripped, so in the end I had to finish the bounty run on my own. Look for communities or clans, and you'll find plenty of people to play with.