Endwalker's message (spoilers!)

[Theodric]

For the rest of the antagonists I would push back against the idea that they all suffered so dearly that comparisons between them and the Scions are insulting or laughable.

The vast majority did, since the story is written in such a way as to conveniently have the protagonists overcome whatever is sent their way for the most part with minimal losses. If not for the Warrior of Light, Limsa would have been wiped off of the map by the likes of Leviathan and Titan. Or at least heavily damaged. The antagonists not having the Warrior of Light to solve all their problems, however, ensures that their story is far more tragic as those that they're in opposition to. There's heavier stakes, more meaningful losses and extensive damage.

In general, I sympathise more with genuine underdogs rather than those who position themselves as such despite not really losing much by comparison.

I'm also not sure why it would be 'insulting' either. Insulting to who, exactly? Putting aside the simple fact that none of the characters are real, nobody is obligated to like or dislike specific fictional entities. Especially if we're seeking to be entertained.

For example, I was indifferent to Moenbryda so it felt forced to me that she's brought up so often, especially when everybody else is expected to 'move on' and not seek vengeance (but somehow it's conveniently fine for the Scions to cry and scream and threaten to take revenge on someone they care about).

Emotional manipulation as a storytelling device doesn't work on me, either. I had a big grin of disbelief on my face as the Scions were 'sacrificing' themselves because it was obvious none of them were actually going to die, so it all felt like meaningless padding and the same sort of fake stakes that have made many Hollywood movies bland and predictable.

So, yeah, I'm not going to pretend as if the Scions' losses are anywhere near as tragic, drastic or relevant as entire civilisations/planets being wiped out completely. Others are free to think differently, of course - but I doubt there's going to be a consensus when there's a global audience with people from all sorts of different countries, backgrounds and belief systems. Different characters and factions resonate and appeal in a varied manner with that in mind.