When I say residential IP addresses, I mostly mean proxies using residential IPs, which allow scrappers to mask themselves as organic traffic.
Edit: Your point stands on there are a lot of services without these protections in place, but a lot of services are protective against scrapping.
Centralization is a weakness. These services can be targeted by governments that want to limit communication. Free speech is a commodity, and servers host this free speech. If a hostile organization, such as a government, targets a channel of free speech such as those hosted on a platform that makes it easy to setup a mastodon instance, this become an easy target that will affect a large portion of users. If you are serious about freedom, you have the freedom to self-host your own platforms.
Edit: I realize my post doesn’t answer the question proposed, but it’s more of an argument against such services. I would argue self-hosting doesn’t rely on paying third-parties to host your software, but I guess this is in the eye of the hoster.