There's the usual fact that the more extreme or fundamentalist someone's viewpoint is, the more like they seem to want to yell it (and the easier it is to say it, concisely). With cryptocurrency, I think that there are many people with a financial and/or political stake in it, who argue from a technical perspective about the merits, so the usual-moderate person senses this disingenuousness and, annoyed, responds more negatively than they usually would. So, in other words, the same dynamics that drive polarization on contentious political issues apply (and I'd actually argue that cryptocurrency is more of a political issue than a technical one).