The New York Times has commended Facebook for banning gun ads in an editorial Monday
I found the comment that Facebook came late into the world of “person-to-person commerce” interesting, compared to Craigslist, which has long banned gun sales. And the ban, if observed by users, might prevent some tragedies, since the sales had been outside the control of laws requiring background checks, even with Obama’s new order.
I remember one time in 1985 selling two gold krugerands person-person at a clandestine meeting in East Dallas. It’s no something I’m into, because, maybe a bit sheltered, I haven’t opted for the sharing economy.
As for public safety, I think it's a bit of a tradeoff, even if "the common good" is the objective. The public as a whole might be safer from ordinary crime with stricter gun control, but might be more vulnerable to very determined criminals and terrorists. That distinction is less in countries where gun ownership is higher.