This is a dangerous short term move. In the end it may create a division and popularize other social medias where this content and worse will still be available in an unmoderated space.
I had to update a Windows 7 laptop recently and the process was far from easy, the update process hang at 100% cpu for hours and I had to manually install the monthly update rollout, average people won't do that and just disable the updates.
The technique is not about the initial validation of a self-signed certificate, its about a pinned self-sign certificate that you trust but want to be able to revoke in the future.
For web site with authentication (e.g. bank account), protocols like SRP (Secure Remote Password) would prevent the man-in-the-middle if he doesn't know your password. SRP is a mutual authentication protocol with zero knowledge and forward secrecy, it would be nice if major browsers supported it, it's not usable without browser support.
I think people don't realise how far we are from an autonomous form of artificial intelligence, even if we knew how to create a self-thinking machine, we don't have the hardware yet to make it work. While it's not impossible that we achieve it one day, its more plausible that we'll blow off the planet ourselves or that we get hit by an asteroid.
This AI debate is a hype right now, but I think it's missing the point. What we need to consider is how the realistic advance of AI will affect our lives. It's not about if machines will take over the planet, it's about if it's gonna make us lazy, stupid and unemployed.