The power of fake news is the emotional charge

How is it that fake news infects people so easily?

The vast majority are created precisely to infect. They are highly emotional, polarizing content, sometimes appealing to some grain of truth, but presenting it in such a way that it instantly excites people, spurs them to act and pass it on, completely without checking. They are also often imaginative, visually appealing.

Often they are also very dangerous, because this content that is carried can cause a lot of evil.

Here I would argue. For the most part, they have negligible coverage. There is a great deal of fake news that gets lost somewhere, just like real news. It's that some topics are "on the one", but others land somewhere further down the line.