You are right it doesn't (of course you conveniently missed all my other points...), well they should make the volume work from the lock screen too. Easy and end of story.
Btw if you go to a meeting turn the volume down before hand? What's the big deal?
What you describe is a falacy, the ipad is not going to ring and ring so you want as fast as possible to turn it off like a phone.
Here's your scenario, you get a notification in a meeting, ipad beeps once,
*beep*
your scenario:
oh I need a dedicated switch to stop that (no other beep sound come of course, it's not a phone to keep ringing), I can't use the volume button I have to unlock first, ok great (nothing is ringing as you think all that), apple has now a dedicated mute, I press it cool (nothing still keeps ringing)...a, ok.
my scenario (even without the volume working from the lock screen), *beep*, click, swipe to unlock, hold the volume, end of story.
Now let's see the lock button.
You pick up the ipad as a young professional for presentation, oh you 've forgot to lock it and it switches orientation when you tilt it one way to show a client sitting at an angle or when you hand it over to someone. Flick switch end of story.
your scenario, ok sorry for that, let me just double click here, swipe once, let me touch this button, click on the screen again, ah hear we are...after ten minutes...let me also show you a portrait drawing of this design, let me just double click, oh I am anxious about the presentation and I single clicked, let's go back, now I ll double click, swipe, unlock it, now let me turn it, oh let first touch it to go out of the screen, oh wait but I want to lock it too in that orientation let's double click bak swipe, lock it.......