I mean, you could argue that it's not fair to discriminate entire countries because of the lax abuse policy of their ISPs, but the comment is correct: that's the reason those countries are discriminated against in this context.
When I was a sysadmin for a few admittedly-not-highly-popular websites, there were definitely more unwelcome bot traffic from US and EU IP's than there were from any 3rd world countries.
I also don't agree that social media "like-factories" should be a concern for Cloudflare at all. Even if they are truly a concern; social media "like-factories" are probably human-operated on third-world countries or bots that are likely running from developed world servers with access to cheaper bandwidth and IP's.
Browsing from a cafe, using VPN results in almost every attempt of following link from HackerNews in solving endless captchas. It is like being harrassed on the border control just because you have the wrong passport.
Saddly many of the sites "protected" by Cloudflare are interesting personal sites owned by honest people who had been scared about dangers of traffic from bad places.
Cloudflare is running internet protection racket Al Capone style.