Most recursive DNS severs on Internet can be categorized in two groups: local DNS servers, offered by Internet providers to their users, and enormous "generic" DNS like Google's 8.8.8.8. When someone makes a DNS request to those servers, they will in turn forward it to DNS servers of web page you are requesting. Content Delivery Networks use DNS to determine, which server should serve your request: if your DNS request arrived from Africa, CDN's DNS server will return IP in Africa. Of course, _users_ don't send DNS requests to CDN's server — recursive DNS servers do. In the past almost everyone used DNS, offered by their Internet provider, — CDN's had to use GeoIP or even static lists of providers to determine origin of that request. When world-wide DNS servers like Google's 8.8.8.8 started to gain popularity, that approach was broken, so EDNS was developed.
Cloudflare is a CDN. They are selling their CDN services for money. At the same time they are encouraging end users to use free DNS server, that does not support EDNS on purpose (they admit so on their website). In effect they are creating a situation, when competing CDNs are at disadvantage and can't determine, what country user comes from. Cloudflare itself does not suffer from that disadvantage, because they control both 1.1.1.1 and DNS, used by their clients' websites.