One of the most enduring and consistent arguments that the antis use to rebuff any Elriel moment as significant in any way is by saying their favorite: well, Azriel would've done it for anyone!
'he would've saved anyone!'
'he would've protected anyone!'
'he cares about everyone!'
'Elain's not special, Azriel does it for everybody!'
The problem with this argument is of course that he doesn't. He doesn't care about everyone and he doesn't do things for everybody.
Everything that he's done with Elain IS unique. And hence, has been given a lot of page time and explanation.
None of his behaviours with Elain are what he usually does with others, and therefore, we, as readers, are meant to be constantly aware of it. That's why SJM uses the words 'never' to describe his actions or reactions.
'Azriel never have that dagger to anyone'.
'I've never heard a sound so joyful' (when Azriel laughed at the headache powder)
Azriel never acted the way at the table, making everyone wait until Elain arrived.
They talk about it because it's UNIQUE.
Exactly the opposite of him doing it 'with everyone'.
He certainly doesn't sit with anyone else in the garden except for Elain.
He certainly doesn't volunteer to go and rescue anyone from certain death. He didn't lift a finger to save Gwyn or Emerie or Nesta from the Blood Rite. He didn't volunteer to go to Oorid, but had to come along and draw straws. He didn't particularly want to train the priestesses but was asked to do it.
He absolutely does NOT give up his siphon and deliberately weakens himself and his powers in order to get to someone faster.
It's only with Elain that he is dripping blood from his wings but is still cradling her in his arms, though she is perfectly capable of walking, so much so that Rhysand, his High Lord, needs to wrench her out of his hold, so Azriel could get medical attention.
It's only Elain's powers does he understands and actually names. Mind you, he, for example, never named what Nesta's 'power of death' was.
It's only Elain who gets Truth-Teller handed to her, and only to her, directly to her, exclusively to her. It's only Elain who is TRUSTED with TT for that one day, and it's Elain who understands the assignment, uses TT as it was meant to be used and then returns it to Azriel.
It's only Elain's bond that Azriel's scents and suffers from.
It's only Elain's gift that he keeps on his nightstand to look at every night. Not Mor's daggers or towels.
That's where the antis are very very wrong. Because Azriel, in fact. wouldn't do it for everyone.
The only person he does everything for is Elain.