Hate elves?
I LOVE elves.
Butter basted and cooked over a low heat for several hours, the meat just sliiiiiiiiides off the bone.
Oh you mean in social settings?
*ahem*
I don't think it's a matter of everyone hating all elves, though there are certainly groups out there with an ax to grind with the treehugger bridgade.
Rather you have to look at a series of situations that accumulate for the mistrust.
Elves are the pretty poster child for metahumanity. They get born as elves, they never had that awkward goblinization that orcs and trolls got in the early days and are generally well accepted, if not held a bit in awe by many still despite them being around for a while now.
The rest don't get the same respect.
While dwarves have no real strikes against them, their smaller stature tends to have people relegate to a lower status or just overlooked in general.
Orcs and Trolls are perceived to be big and brutish, considered not too bright regardless of their achievements.
They rarely goblinize anymore but due to the appearances and preconceptions by many folk they are usually treated as second class or lower as knee jerk reaction.
It doesn't help that some elves try to play it that they actually are superior and some can be real dicks about it.
But again this is not common to all elves and there are some Orc or Troll groups with similar attitudes, but they are tiny in comparison and usually are relegated to ganger levels of operations unless you make a trip across the Pond to the Old Country to check out some of the Troll kingdoms, while the elves with this sort of attitude hold two countries of their own, the Tirs and their gang of the Ancients serve some of those powers.
Elves also get a lot longer lifespan, a bitter counterpoint to the shorter lived orcs.
Now it is rare for any runner to die of old age, but some will still resent what it represents.
Then you have the Immortal Elves which is a whole basket of woes unto itself.
They are a plot device and a well used one, but it can grind some people's gears to think they are being pushed around as pawns.