Thanks for highlighting this. It's a ticket from two years ago and this thread is a good opportunity to share more of the context and intention of how we think about Team Edition vs Enterprise Edition.
I've shared a reply on the ticket here: https://github.com/mattermost/mattermost-server/issues/6320#...
Also, I don't know if the ticket title is highly accurate--a non-admin can't delete any channel:
1) There is no "Delete Channel" in the UI only "Archive Channel"
2) A non-admin cannot archive any channel, only channels of which they are a member.
3) A non-admin archiving a channel they created is not really an issue, so this ticket is really about a "Non-admin can archive a channel which they are a member of but didn't create" which we've seen can be more helpful than harmful--when someone leaves a team and their out-of-date channels remains anyone can go and archive them without having to find an admin and make a request.
The current wording sounds like non-admins can delete private channels, channels on different teams, channels they're not part of, etc. and in my mind it's not the case. But perhaps other people have a different read?