Homophobia doesn't have to always exist in a society, maybe elves don't give a shit.
Eh, I don't even want to rant about everything else. But let me give you a quick reply about this.
LOTR mythology is very clear. Elves are Tolkien's exalted christiandom to the extreme. They literally vanish if they have sex outside marriage (which by Tolkien own words mean the union of two people to have babies), and as seen with Arwen and the other 3 elves that we know of, an elf that tries to have any other kind of romance outside elvenkind
falls from heaven losses their immortality and is fated to not be a part of elvenkind in life and death anymore.
Which I really doubt is something she would do just for her bestie. Though you can also retcon her out, then Aragorn needs to do his duty as a king... So you also need to deal with his feelings regarding adultery since he was raised by elves. You can make them gay, yes. But you can't ignore everything else about the setting.
Curious fact, elves can marry whenever they want and without witnesses. They kind of just do the thing and get married. But they are strictly monogamous (as said above, they vanish otherwise)
If you want to make some Legolas smut, go ahead. But if you try to make a real story while trying to care about the source there are many points that shouldn't be ignored. Like the simple fact that he either gives his immortality or just haves a completely platonic relationship.
So yeah, Elves do give many shits. But none of them are about gay elfs, you can bet all of them would mourn and support a gay elf existence since he wouldn't be able to find real happiness in marriage or a partner within their own.
Then learn to remember what you said.
We are talking about
literary characters, not people.
So yeah, if you take, let's say:
Jiraiya and suddenly make him gay, you can't completely ignore his background as a serial womanizer and self-acclaimed super pervert. You can just say, I dunno that he was afraid of his own sexuality. But you need to deal with that and
not ignore it.
And absolutely, definitely, not just make a character gay out of nowhere in the middle of a fic, which was what I said.
You either put some foreshadowing, or just goddam say it since the beggining at the very least. Because when you find a good fanfic and then 8 chapters in the character, absolutely out of nowhere, becomes gay and starts pinning for the dark edgy antagonist boi almost to the point of genre shift, you definitely need a reason for it. And that is one of the biggest faults of gay stories I find.
And this is not only for m/m, but also f/f, and heck, just characters in name only. You need to write against the Willing Suspension of Disbelief from the readers.
And that is called literary consistence. When you are reading fanfiction, you have the notion that any fictional concepts, characters, or settings borrowed from other works should behave as they do in those works.
If they don't, you need at least a reason (which is the basis of most fanfics "let's change this for this because of this"), or to tag it at the very least AU and explain that.