latest update

It seems you are not deleting these emails form your junk folder, but rather you inbox. I do not ever recall there being a way to delete all messages in an inbox other than junk, trash, etc., so I suggest you log into a Mac computer and select the first junk email, then press shift while clicking the last email you want to delete. It would select all of them and you could press command+delete.

As in, pressing edit in your inbox but tapping each email to select it and then archive/trash?

Ah. I see what you mean. That really is unfortunate Apple took that feature away! (Even though I myself have never used it, especially the procedure requiring holding and taping multiple times, etc.) With that, I can highly suggest that you go over to www.feedback.apple.com and tell them about this. You never know, they might put it back in a future update! Sorry I couldn't be more helpful...