Hey the Linux community is active so they show up on All. Same thing with video game communities, it's a reflection of the interests of those who populate Lemmy. I don't care for either but we gotta start someplace. IMO it's largely due to the concept of the fediverse and instances and not simply an app you sign up to. FWIW, I barely get it. Folks here seem to be a tech savvy bunch
They accost posts en mass that have nothing to do with Linux CONSTANTLY. It's actually really, really obnoxious, and it's absolutely chasing people away from this platform.