@evan Because you haven't seen them doesn't mean they aren't out their in abundance. Doing simple user research you quickly find this model is really problematic for people thinking they were private, it is an amazing tool for stalkers to take advantage of and oh they do. The stories are abundant and can be brutal.
Following bad practices and putting people at risk isn't great. People are looking for a better social platform that has their wishes upheld, not another that breaks them.