Please understand that I do have a Junk folder in each of my accounts. I also have sent, drafts, etc. That is not the issue. so, when you say select the mail in that junk folder I take it as either: 1. highlighting the junk folder to see the emails that are in the folder and either going to "mailbox" and selecting "delete junk mail" or using a two finger click to bring up a box that says "delete junk mail". Doing either of those actions delete the junk emails in all of my junk folders in all of my accounts.
Or
2.selecting all the emails in one junk folder and hitting delete. That works to delete the emails in just that folder, however, the act of selecting those emails opens each of those emails which obviously is a very risky thing to do. That is not something I want to happen.
I use thunderbird email client on a linux computer and I can delete junk emails from any one of my accounts individually without risking opening any of them. I was hoping that there was a way to do that with Mail.