This is definitely a "my opinion" type of thing, but I dislike the concept of metaphysically evil (or metaphysically good) in the first place. I recognize that this IS a concept in D&D, I'm just saying that I don't like it.
I prefer to say that dragons have tendencies that put them at odds with other creatures (and with each other) and end up acting in a way that we would agree is basically evil*. You could probably still justify killing a wyrmling with by saying that as an adult it will be too late to kill it, and it will be a menace then. I don't think I buy that argument in all cases, but you could certainly make it, and most people in a society ravaged by chromatic dragon attacks would kill the wyrmling as a matter of habit.
*the primary reason I prefer this is that it gives dragons "free will" that is clearly lacking if you assume that they are metaphysically evil.
