Homegrown = imported.
I don’t know. I read an article yesterday about several ditzy white (that is, non-ethnic Muslim) women in Colorado who had converted to Islam recently and were on their way to the ME to “do jihad” when they were apprehended. Must be something in the water.
That said, yes, a lot of these people they call “homegrown” are actually simply immigrants who are living here on their (expired) visas and are not really what one thinks of as “homegrown.”