Literary journals are typically staffed by undergraduates who are learning how to be editors of literary journals. They have other things to do in their lives besides read submissions. Somewhere in their day they are expected to attend lecturs, read great literature, and write essays.
Given the situation, it's no wonder that it takes forever to get a response back when you've submitted a short story in the hope of getting a credential. Knowing that you'll have to wait, you sit back and do just that.
The time grows longer. You haven't been rejected yet. The submission requirements suggest that you'll know in five months time, unless they are interested in your work.
Five months goes by. You wait. It's looking positive, if they've kept you dangling past the expected time.
If you don't hear from us, they said, so I asked after the short story that was sent six months ago. Oh, they replied. So sorry. We rejected that in less than a month. Don't know why you didn't get the rejection e-mail. Do please submit again, though. It wasn't the worst writing we've ever seen.
Most journals don't accept submissions in the summer, when the interns have all gone home to earn some money to help them pay for college and work as unpaid interns during the school year. Rejected at one place, and the short story will be sent to several other places. Must rush, to beat the deadline.