He thinks LinkedIn is cringe (fair) but has a position where he can ignore lots of professional norms. LinkedIn is cringe because people are deliberately trying to respect professional norms and post weird, sanitized, work-appropriate content.
Imagine you’re a recruiter. The selling point of X jobs is that they will give you access to people who found professional norms too hard to follow? And probably some specialists who would be hard to recruit, but maybe they get income that’s a multiple of several boutique recruiting agencies from that.
This isn’t like stackoverflow jobs where the base is correlated with technical expertise - X jobs is correlated with people who are terminally online who think being polite in their work-facing lives is something that people don’t actually want. What hiring manager wants to draw from that pool?