This is not true. Twitter scans a person's tweets, bans, likes, etc to pick out "interest" categories. If someone tweets on various topics, they will have a lot of "interest" boxes. Twitter uses these to display "relevant" ads to users.
When Dem ads appeared on my stream, I blocked those users. This created a "conservative" interest box for me. When I had an argument with someone who claimed to be conservative, this removed the "conservative" interest box for me.
It's really creepy how this feature works. That is not how they throttle.