I think embracing and valuing the principles of FOSS, decentralization, anonymity, privacy, ownership of one’s digital identity and data, online security, etc. requires a degree of technological literacy that most people don’t possess. For most online citizens today who’ve only ever known the current centralized Web 2.0 through the glass of a mobile device, convenience trumps those principles even when you explain their value to them.
The Meta crowd and the Fediverse crowd are not two perfect distinct sets - more like a Venn diagram with some inevitable overlap.