Ding!
In a fantasy world, evil and good can be more prevalent and known based on racial characteristics. The majority of each race had specific propensities, but there were minor exceptions.
Gollum was evil because magic twisted him that way (he also had tendencies that way to begin with).
Exactly, he was a unique, twisted thing, not a race. If he was any race, he would be a hobbit. Thus, they knew he was evil. He had been made evil. If they had not known that, I bet they wouldn't have thought badly of him. Bilbo didn't really think of him that badly in the caves before he knew.
Elves were good.
Dwarves were good, but greedy.
Hobbits were good.
The way nothing can be just evil, nothing can be just good. Wouldn't go down in my worlds either.
For simplicity sake, many players and DMs play Elves and Dwarves and every other PC race as if they were Human with Human foibles and Human thought processes (because we are Human, that's what many of us do). But, different races should have extremely different alien thought processes and because they do, just like in real life between people with extremely different thought processes, conflict should arise.
Oh definitely. I never said I don't put a lot of conflict in. This is totally different from a race being all evil or all good.
The Dwarves hate the Orcs because they compete for resources and have been at war for thousands of years. The Dwarves tolerate the Elves (in certain campaign settings) because the Elves being one of the good races has helped the Dwarves fight Orcs in the past.
This, exactly, is what I am going for in our games. Conflict must make sense.
Playing all other races as if they were Humans with pointy ears and no other non-Human mental and emotional features (and especially with 20th century inalienable human rights for everyone thought processes) kind of defeats the purpose of rolelplaying. It becomes totally game mechanical at that point.
Bad roleplaying has nothing to do with evil or non evil races. It is just bad roleplaying and can happen everywhere. But in most cases it works out quite well.
I remember a game I played in where, on the front, the PCs seemed to have little conflict despite being from all different races. But their diaries, letters or other ways to contact home, usually done at the end of a session, were always hilarious, constantly complaining about the other party members, wondering why they did what they did ("something is wrong with the elf, saw him hugging a tree today" "the human insists on doing her 'private business' in the woods alone every day. Wonder what she means by that? Maybe she's praying' are just two unforgettable examples).
Playing races with a self motivated racial bend where every race has its own self interests as a race and is competing with every other intelligent race for resources results in a rich campaign world that's logical. Playing races as if many individuals of most intelligent races can be benevolent to other competing races is illogical.
I don't think it's illogical at all. In some settings, all out competition is fine, especially where resources are very scarce. But given the, usually, 100s of years those races live next to each other, they should have arrived at the concept that working together is beneficial in most times.
In the real world, people have no qualms about killing sharks because sharks are viewed as man eaters and killers.
That's not quite true. Most people with a bit of brain just avoid them, especially as you kill one, you attract more of them
All of these should be the real world equivalent default in a fantasy world, just like gravity normally is. The primal motivation forces in the real world should have fantasy world equivalents. Enlightenment and tolerance is caused by cooperation, commerce, communications and the rule of law.
And experience, and there is plenty of experience in many of
my worlds telling members of different races that cooperation is better.
Personally, fantasy settings like Eberron where there are cities like Sharn where every intelligent humanoid creature is protected by law is nonsensical. A Lich walking through Sharn should create panic in the streets, not just be passed on the street by the locals with "Hi Joe". But in Sharn, that Lich is protected.
That's why I love Sharn so much.

Being protected, btw, doesn't have to mean people like it. The Sharn we play in right now generally shuns the undead, so they might even try and kill the lich and pin it on someone else. In our Sharn, the protection is there to appease all nations.
In a fantasy world with fiefdoms or kingdoms like Eberron, protecting of races that come from outside of ones own territory would not be law. Outsiders would be viewed with suspicion because they could be spies for other kingdoms.
How well do you know Eberron? From my experience with that world, there is PLENTY of suspicion, but, aside from a weariness about the warforged and certain undead, it is not based on race but on allegiance, religion and the like. In some areas, if you are not of the majority race, you get a lot of looks and might be bullied, but that's because usually the majority, not all, of your race tend to be of a certain world view/religion.