It's an overreaction -- people want to have their cake and eat it, too. The thing is, you can't participate in this connected, global world with all its benefits (including an immense amount of available information about everything, including people who have participated in it) and then undo your participation in this information sharing economy. It's an attempt at time travel / rewriting the past, and it's expensive and ultimately impossible to do perfectly. Furthermore, it is unfair to the other participants in this information economy who expect reliable, consistent information.

Exceptions for slander and copyrighted information (e.g. photos) that were posted by other users? (or even regular content posted by the user that they 100% own) Absolutely -- but even in these cases, requiring that the third-party platform owners track down all potentially offensive content (much of which may be posted by other users) and then purge every layer of their backups after removing the offending content is overkill and shifts the responsibility away from the offender (whoever posted the content, even if it was the user himself) to the platform owner.

Ultimately, the ability to un-publish content you own that you published should be sufficient regulation-wise, and most popular platforms already enable that as a basic feature.

Is it? Before all this tech only specific targeted effort would store information about me. Now everyone is tracked by multiple entities all the time.

It's not about undoing participation in information sharing. GPDR does not require Wikipedia to delete everything I've contributed, but the fact that I have contributed is subject to be deleted if I request so. Furthermore, there must be explicit opt-in, and that is a good thing.

It's a trivial problem to purge from the backup, really. It's not a hard problem to solve. Many companies have done so before, and now we might even see standard tools to do so.