Users aren't meant to manually manage apps. Perhaps it should not even be offered as an option in the first place, except as something like "force quit" of last resort.
Apps are shown by recent-use, so that takes care of "which I'm using for this task now".
Users have to do what users have to do though. Apple may not mean for them to "manually manage apps" (i.e. killing apps; not some monumental task), but there are plenty of reasons for users to need to do it which are listed here and in the article comments.
So why are we making it harder for them to do things that they definitely need to do? I think the only opinion we've heard so far has been "because that's what Apple wants users to do".
This is typical Apple - they are totally ignoring what users actually need to do and acting like it's a superior design. Next thing you know, they'll provide no means to resize a window by any corner or edge on Macs. Then Apple evangelists will defend that decision for years and years as if it were somehow better (or "just different"...but definitely not worse than anything else!)
Apps are shown by recent-use, so that takes care of "which I'm using for this task now".