There are evil mobs in there too. I've seen tons of "forest protector" wood-elf roles. You may define them as "good" roles, but let's look at neutral for a moment.

Many CF'ers play neutral as "kills as much good as he does evil" but I don't think of it that way (necessarily). I see neutral as someone who maybe is good 90% of the time but 10% of the time chooses not to aid good or "do the moral thing" because of several types of reasons. Two come to mind immediately:

1. Neutralguy sees the "big picture" - ex. letting that sickly orphan die means more food for the other orphans, ensuring a better chance of survival for them, and realistically, the sickly one is going to have a miserable life and probably die anyways. Someone who is playing "good" will almost always want to save the sickly orphan and then try to find more food for everyone yadda yadda.

2. Neutralguy cares more about (insert non-alignment goal here) than good or evil. Neutral ragers are a classic example of this - "No, I don't hate elves, but I sure do hate elf mages." Outlanders too - "I like my elven Sunwarden friend, but that Tribunal Storm Paladin needs to die, because he's just a pawn of the system. The Man is keeping me down!" Tribunal too, of course, for the opposite reasons.

There's all kinds of player motivations. If you are concerned about it, you can write into your role why you do the things you do.

More people get screwed and turned evil for doing evil things than for doing good things, generally.