Author here: In developing this I discovered that Twitter really doesn't care about lists. The limits on API usage and aggressive following are well documented, but anything about lists is minor. Also, if anyone from Twitter is reading: it would be nice if Twitter implemented a way to subscribe to someone's timeline instead of having to resort to this method.
Imo they realized it doesnt work for their users core usecases that well. Therefore they removed efforts. The problem here is in the end that there isnt a easy way for a company to communicate it's product strategy to api users and people are left to reverse engineer it.
It's like they gauged interest on half-an-MVP of a feature and never bothered to truly complete it and make it actually useful.