I’ve lived in Vietnam for the past 5 years and experienced these issues first hand. I’m also part of the team responsible for maintaining a relatively aggressive set of Cloudflare WAF rules at my current employer.
In these developing countries, great swathes of users are accessing the internet behind carrier-grade NAT.
This makes it increasingly likely that any individual user is sharing a public-facing IP with one or more bad actors.
In my experience, I’ve never had to solve more than one CAPTCHA per domain, and frankly clicking a checkbox isn’t that hard.
As far as discrimination goes, this is a much friendlier solution than just immediately rejecting connection requests from certain CIDRs, which is what would otherwise be happening.