I think it's more of where you choose to be outspoken. On Facebook you can post updates on important life things, things no one cares about, or even touchy subjects without much fear of being harassed. On places like Reddit, or deeper down into 4chan, or other sites that are known for their 'lynching' it gets riskier to be so 'outspoken' with your real identity because there are larger quantities of people that you don't know that are way off from your personal network thus making the possibilites well endless.
When it's an accepted peer to peer network it's different from either a 'real' user to anonymous user or anon user to anon user. The more anonymous people are, the more brave they become but as soon as their real identity is attached, things don't get quite so serious, at least not in the main factions of social media. The Wizard in Oz is a good example of how you can hide behind a figure or 'name' but when the curtain is peeled back, it turns out you're not much better or different than anyone else.
edit: added some more to hopefully make my point more clear.