What changed is that the bulk of human communication now is happening on the Internet. And the Internet itself is concentrated in the hands of few companies. And there is an increasing sophistication of actors who play the system.

This means that political and societal activism is now manipulable at scales that were inconceivable some time ago.

So the human factor has always been there (and arguably helped us when the memes were like "kill the sabertooth tiger!"). But the problem is growing because of technology, which is another thing that cannot lightheartedly be slowed down.

So the least we can do is to be aware and minimize the damage