The idea that the half-elf is disowned by both its parent species is about as outdated as the nonsensical elf/dwarf hatred.
Honestly, even if they do introduce some variant of half-elf and half-orc (hopefully, in the context of some grander system of hybrid species) I hope the whole "you are hated/feared by your parent species" backstory gets chucked in the bin.
Where does this idea of disowned/hated feared come from?
I think it was
@Hriston who posted the info from AD&D upthread:
Monster Manual (p 39): "All half-elves are of human stock. They are handsome folk, with the good features of each of their races. They mingle freely with either race . . ."
Players Handbook (p 17): "Half-elves do not form a race unto themselves, but rather they can be found amongst both elvenkind and men. For details of the typical half-elf see ADVANCED DUNGEONS & DRAGONS, MONSTER MANUAL under the heading Elf."
And on the racial preference table (PHB p 18) Elves feel
Goodwill towards Half-Elves (the second-highest level after
Preferred). Human attitudes are the next level down,
Tolerance, meaning that among humans Half-Elves are "generally acceptable, if not loved."
The 4e D&D PHB says this (p 43):
Half-elves usually adopt the dress and hairstyles of the society they spend the most time with . . . Half-elves have no culture of their own and are not a numerous people. They usually bear human or elf names, sometimes using one name among elves and a different one among humans. Some are anxious about their place in the world, feeling no kinship with any race, except other half-elves, but most call themselves citizens of the world and kin to all.
That is more fleshed-out than AD&D, but doesn't imply rejection or dislike by others. The same page also says that
they are charismatic, confident, and open-minded and are natural diplomats, negotiators, and leaders. . . . They like to establish relationships with humans, elves, and members of other races so they can learn about them, the way they live, and how they make their way in the world. . . . They are generally well liked and admired by everyone, not just elves and humans. . . . Half-elves naturally inspire loyalty in others, and they return that feeling with deep friendship . . .
So that's pretty much the opposite of the rejection/dislike thing.
I had a look at
the D&D Beyond page for Half-Elves. It includes this: "Half-elves have no lands of their own, though they are welcome in human cities and somewhat less welcome in elven forests." That last clause can be read a few different ways, and is not as strong as rejection or fear.
The 3E PHB (p 18) is similar, though it changes the source of possible wariness, and is also a little bit contradictory:
Half-elves do well among both elves and humans . . . In human lands where elves are distant or not on friendly terms, however, half-elves are viewed with suspicion. . . .
Half-elves . . . are welcome in human cities and elven forests.
Pulling the 2nd ed AD&D PHB of the shelf, I see that it is pretty similar to 1st ed except it adds the following (p 22):
in some of the less-civilised nations, half-elves are viewed with suspicion and superstition. . . . Half-Elves . . . can be found living in both elven and human communities. The reactions of human and elves to half-elves ranges from intrigued fascination to outright bigotry.
That last-quoted clause contradicts the earlier observation that "They mingle freely with either race" which seems to be taken directly from the AD&D Monster Manual. Nevertheless, maybe it is 2nd ed AD&D - influenced by Dragonlance? - that introduces this fear/rejection notion.
