I think what we see here is the result of social media A/B testing on how to get votes, and this playbook is now followed by the rest of the world.

In a democratic society, you have to influence the public opinion to stay/get in power. Propaganda is free, information costs money.

If the majority of voters are not willing to pay for quality journalism, you have to get them engaged by fueling outrage and projecting fear. It doesn't matter what side, as long as there are sides you can join and identify with.

Combined with the fact that American politics do have an effect on the quality of life in other parts of the world (trade wars and refugee crisis for example) and the working (aka non-capital) class suffers in most western societies, it is very easy to project similar fears and foster divisiveness.