Why? It's because they never arrived at their current behavior by a systematic progression of logical steps. Most of the behaviors we exhibit aren't that way. We just offer a post-hoc explanation/justification. They use edge, so they defend their action with any argument assertion they can think of.
It's also (sort of) because they want to tip the proverbial scale towards their current use. Change takes effort and can be irritating. They have their list of positives about edge (faster, easier, etc.), and they downplay the negatives such as privacy.