An established platform's most valuable asset is the data of the userbase.
Twitter can leverage a huge amount of data about personal preferences, interests, relationship status, political leanings, income, usage profiles, message habits and content, social graph, and location.
If you specifically wanted to clamp down on certain demographics, it would be an excellent way to locate them.
Can't have a large data trove on your users without users. A huge part of a successful social network is sufficient adoption. If the people your users want to follow aren't on the platform they don't have a real reason to be there. It's a major hurdle for any new social platform and a lot fail at that step.
Twitter can leverage a huge amount of data about personal preferences, interests, relationship status, political leanings, income, usage profiles, message habits and content, social graph, and location.
If you specifically wanted to clamp down on certain demographics, it would be an excellent way to locate them.