One way to look at this is, "Look how bad this browser behavior is for users! We should eliminate it to protect them."

Another way to look at it is, "Imagine how horrific the impact of this problem is going to become as researchers and criminals weaponize it. There is no way this browser behavior is going to survive. Therefore, it is a very bad idea for us to rely on it in any way."

It's also a nice clean example of how weaponization, exploit development, and full disclosure can move security forward. The worse this problem gets, the more likely it is that it will get fixed.