That's how radicalization essentially happens. In this case it's self radicalization + Facebook/Google AI bias. Nobody is taking them and placing them in Madrasa with a cleric preaching terrorism and such but it ends up with a similar setup at its core.
I've seen what I considered rational, educated people, including college professors go off the deep end with anti-Trump conspiracies, calling for assassinations, the Russian puppet narrative and so on. And from their point of view it kind of makes sense, their news feeds and circle of friends is telling them those things every day.
People wonder how does a young end up believing blowing themselves up will lead to virgins in heaven and it seems crazy, but this is not too far from it as well. It's essentially the same process.