Most content from .ml users likely isn’t even political, so people certainly overstate how prevalent radicalism is. Lemmy is part of the fediverse and isn’t a reserved political space any more than any other part of it. But you are much more likely to see controversial positions from the “tankie triad” compared to other instances and other social media. It is one of the few big instances where you can find popular support for Russia over Ukraine or denying the Uyghur genocide for example.