I’m still not clear why US companies with no business units in Europe feel the need to make any changes at all to be in compliance with a law that has no jurisdiction over them, but agree that Geofencing is a cheaper solution than asking a lawyer.
They geoblock EU users so that the EU doesn't have jurisdiction over them.
The GDPR states that websites that serve EU citizens are subject to it, no matter where they are. Many US news organizations chose to geo-block the EU rather than going to the trouble of figuring out compliance.
Because they have identifiable owners who might wish to travel to Europe and not risk someone deciding to make an example of them.