Not to give any judgement on whether usage of a CDN is good or bad. But I think it is a bad idea to talk about decentralized hosting and decentralized ownership like they are identical. The problem with social media the fediverse is solving isn’t that all social media goes down when CloudFlare/Facebook CDN goes down. It’s to be independent of one organisation or even person that can ruin the fun for everyone. If CloudFlare bans every instance, the owners are still in control of their DNS names and can just move to another CDN or their own reverse proxy/cache