No, that right is to have info tracable to you personally removed, not to have every word you ever stated removed. As long as they anonymise it, they're good legally and can keep all other data online.

They also only have to send a data delete request to those they shared it with. Any data that got scraped or taken in other ways from them by a third party is technically not protected under that law, and would require a deletion request from you to them. And let now that be the technique used to federate.

Not to forget that the law only counts for services hosted in or aimed at European Union citizen. For example, an American Lemmy instance aimed specifically at American citizen isn't bound by it, even if you join as a European Union Citizen. If they market to the whole world or such, then they are bound by it. But then, with a US-based server it's already nearly impossible to be GDPR compliant as US-law is by default against GDPR. Hence big SNS's having EU subsidaries and servers (and still have huge disagreements, lawsuits and fines about how data gets shared between those and non-EU servers). Point being, with defederated systems, there are bound to be servers with your data that are outside the scope of the GDPR. The whole thing is more complex than "I live in the EU so all sites need to comply when it regards me".