We get it. It's bad to take the fish outta the water in the cold. But you're simply not acknowledging the irony of quoting "fish health specialists" as we all hook fish, drag fish, land fish and toss em back to do it all again. Got any quotes from the experts on breaking your line while fighting a fish for your enjoyment, leading to the poor fishy dragging 2 feet of tippet around with a sucker spawn fly and hook attached to its mouth? Perhaps foul hooking one in the "south mouth" and embedding that nymph up its a__? Or has that never happened to you?
Again, use proper wisdom and judgement, yes. But crying injustice about someone risking a fish's health while we all do things that risk a fish's health is "absolutely incredible."

is it better to take a hero shot and return it to the river....or slap it on a string?
 

Trick question BB.
 
If you are doing irreparable damage to the fish before returning it to the water, it is a dead fish either way.
At least if you take it home it will be put to use.
That said I'll take door number 2.
 

I'll support troutbum on this one.  I was up there in early December and would freak out if my pops had the fish out of the water too long for a pic.  Also made him lose a fish because I didn't want him to bank the chrome.  I was handling the leader, the fish turned and snap there goes the 6 lb test.  I will never live that one down... 
 
I will say this....  I suspect the guide was doing whatever he could to make sure his clients enjoyed themselves.  In early December I was fishing mid-river.  A guideboat drifted off so I shuffled down to fish a seam noticed a 12 lber struggling along the banks.  I could help but think did the guide do this and if he saw this fish struggling why didn't he just keep her.  I tried to revive her but the outcome did not look good. 
 
Its sort of like the discussion on nets versus banking a fish versus a michigan mit versus a wool mit during the winter steelhead season.  It ends up coming down to how can we inflict the least amount of harm and in this particular case do not hold the fish out of the water for extended periods of time especially during the winter season.