I also don't agree that extremists are particularly good at diagnosing problems. Instead, they tend to be confidently wrong in a way that's exceptionally compelling if you're emotionally vulnerable to their cause. This is why they rarely succeed in creating collective movements that involve broad cooperation and collective structures that can function and endure. They've misdiagnosed the issue, and they typically can't recruit people based on ideological merit, shared purposes, goals with clear outcomes, or other cohesive and productive substrates. They're more like cults and less like cooperative, coherent, purpose-driven organizations. Yarvin and his set fit squarely into this bucket.
These people typically talk too much and don't actually do anything. It's because there's nothing _to_ do when your ideology is a nebulous, discordant, illogical, and emotional dump.