Ser Davos remained totally loyal to memories of Shireen

I wonder...he looked more conflicted than anything.  He had his chance to put her down when she came through the gate and bought in totally to her claiming her death was nigh (alternate course 'I won't let you escape justice through suicide or some sacrifice...Archers knock--LOOSE!') and while he followed her out and put his hand on his sword he didn't draw it and stopped before she started peeling for her last nude scene.

It was kind of silly to blame her entirely anyway, almost no one else returned from that last doomed march, why would Shireen be different?  Would he have preferred Shireen fall into Ramsey Bolton's hands?

Why do you think it was? For whatever reason Melisandre thought the Lord of Light demanded it and Shireen would go to a happy place and play with fawns and butterflies all day.

What makes you think I'm 'defending' that rather than trying to understand its implications?

No one actually died here, Kerry Ingram is alive and well and is a regular on a TV series, a role she might not have gotten had she not been so memorable as the absolutely adorable Shireen Baratheon.

Who actually killed Shireen Baratheon? The writers did.  What effect did her death have on the story? Immediately it allowed Melisandre to escape back to Castle Black where she was able to resurrect Jon Snow who would then banish her when he learned of Shireen's death so Melisandre would have to leave the North and go to Dragonstone so she could 'bring ice and fire together.' Later she could then show up and aid the defenders of Winterfell and most importantly direct Arya towards the Night King which saved everyone in the North if not all of Westeros and the world. If you doubt what that's what they intended remember Melisandre's words about Beric and Bran's words to Jaime and Theon about the things they were sorry about.

I'm not saying it's moral or that I like it but that's the story they're telling; the sacrifice of Shireen ultimately was instrumental in saving the world.

How could that have mattered? So they'd be a little farther up the road when they got snowed in and were faced with the same dilemma?

Storywise the one responsible for all this was R'Hllor, and what I'd really like to do with Melisandre is string her up by her toenails until she gave us some answers.  We know she doesn't have the whole story but she knows more than we do and it would useful to determining just how malevolent a force this R'Hllor is.  Maybe she could help us with The Old Gods too, representatives of which (The Children of the Forest) were responsible for creating the Night King menace in the first place.  What they have in common is they they have an adverse impact on free will, which is why I wonder if in the end the resolution will be their exposure as a detriment to mankind, if the Army of the Dead and the immolations weren't a big enough hint.  That would analogize another popular fantasy author, Michael Moorcock, who had his hero kill the Gods of Chaos (who seemed 'evil') and the Gods of Law (who came across as pretty 'good') at the end of one of his sagas.

If it's truly possible to see the future, our free will means nothing and morality dicksquat; our choices are already set in stone and we're just cogs in a machine unable to deter from our programming. I much prefer David Hume's take on all this as he acknowledged that although often our choices are limited by factors like or akin to our capabilities, upbringing and genetics we still do have them regardless of Gods and Kings.