Ok, thanks, I did not realize that. Still, it illustrates the fact that it is bad design if it is not intuitive to use. I interviewed multiple people and none knew how to dismiss it. Design should be easy to use and understand. I agree with @stevekinney
Furthermore, while you close apps by swiping up, most delete / dismiss actions are done from right-to-left (messages, mail, closing safari windows, etc).
Agreed but what I think they are going for is that it is part of notification center and the traditional interaction with notification center is up or down.