Because European governments are passing/have passed regulations forcing big tech companies to open up their platforms.
(it’s also taking funding from the EU, doesn’t necessarily mean they’re forced to cater only to EU citizens but the combination of these two factors means it makes sense to)
I'm not gonna claim to know much at all about the ECHR, but this compliance graph from Wikipedia makes it look like a symbolic institution, but one that is largely ignored/ not really respected? Especially given that it's a declining trend, it seems like they may just be doing more and more political theater type stuff instead of "real" work. Anyway, it seems like it could somewhat reasonably fall under "governance bleh" depending on who you ask.
Unless I've missed a very recent change, F-Droid isn't geographically restricted.
Much of the blog post focuses on the DMA and its impact on Europe. I think the phrase you keyed in on, and really the bulk of the post, is just a marketing push for the European market and a bit of SEO trying to get keywords and phrases in there.
Ok but why the geographical restriction?