My comment doesn't make a statement about how things should be. It's a statement about the complexities of a technical implementation:

_If_ it is true that the GDPR covers an EU person's data held by any company worldwide, regardless of how or whether it should, an IP block might not be accepted as compliance. Or it might, if the EU regulators decide that best-effort is enough.

The important point is that many Europeans are browsing the net through non-EU IP addresses without the knowledge that they are doing so. Most people do not pay attention to what their corporate public IP address is. They may use "non-EU" services entirely unintentionally, and EU regulators may or may not take that into account in the unlikely case that they investigate one of these companies.