Hello, this question comes up a few times each year. I know it isn't obvious, but the countries that have their own sections in our forum reflect what we cover in the Explore Europe section of our website, which in turn reflects areas we cover in our guidebooks.
General Europe is meant to be the catch-all for European countries that don't have their own section.
We learned when we expanded the forum 10 years ago that over-expansion is a thing. It does no good to create a new section if it doesn't have enough life to it. More people will see it and answer questions for Albania, Romania, etc, if it's posted in a place that gets a lot of eyeballs like General Europe.
Moderation capacity is not a limitation. Aka, we're not making decisions to limit engagement. Quite the opposite. And while it's quite easy for me to add a new section, retraction of a section (due to lack of engagement) is quite difficult. As such, we need to feel reasonably assured that a new forum section can be successful before we add it.
Cheers!