[Frondo]

I also have direct experience with the opposite: an older friend (late 50s), socially isolated, who over the last year or two has self-radicalized into a hardcore Muslim hater.

A few years ago he was just a plain ol' gentle soul, and he liked to watch those militant atheist videos on Youtube (I have no opinion about such). I guess one of them had some sort of anti-Islam recommended video that caught his eye, because I remember the day we went out for lunch and he told me about a video he watched about Islam.

I have quite a few Muslim friends so I spent some time gently dissecting what he was saying. None of what I said stuck. Over the following year, he got deep into the rabbit hole, until how awful Muslims are is all he'd talk about.

I had to end the friendship, despite my efforts to talk him out of that, because that garbage had literally become the entirety of what he was into/wanted to chat about. (Objectionable and boring, hah.)

[hypersoar]

The jump from militant atheists to Islamaphobes is not a big one. A lot of New Atheists, including very prominent ones like Bill Maher, Sam Harris, and Richard Dawkins, have a tendency to single out Islam as particularly worth hating.