I don’t think they fear the mob. They fear wasting their time. Where there are quality discussions you will still see lively discussions. Math is an area where top experts will still discuss online. It’s because they are less likely to be inundated with clowns.
Pop culture and politics is where the mob culture resides.
I vehemently disagree. In my experience, a very substantial number of them fear the mob because there's so much at stake and nobody is interested in falling on their sword. Many people want to talk politics and philosophy and those subjects are often hard to avoid unless conversation is heavily restricted. I've had tons of conversations about algorithms that naturally turn into discussions of political and philosophical ramifications. A substantial amount of the screening that goes into accessing private communities revolves directly around likelihood of charitable interpretation, secrecy and behaviour on public social networks.
I disagree. In fact I spent some time looking online and I think there are more technical discussion I've ever seen online. There is more open source code then ever before and most of that discussion happens in the open. Many of the biggest contributors have these discussions online. I simply haven't seen the discussions disappear from public view as you seem to. Maybe you just aren't looking hard enough to find them?
Pop culture and politics is where the mob culture resides.