In the 1e MM, the metal dragons all have good alignments. I am skeptical. Can there really be such a thing as a "good" dragon?
Here is my definition of a "good" dragon: one that is happy to bully and rob you of your treasure, but won't kill you for fun. They will still attack you, steal your stuff, and beat you down thoroughly, but with a "good" dragon, you are more likely to be left alive.
I get the impression dragons look at us the way we look at chickens. You don't have to be evil to eat chickens. We simply view them as a lesser form of life, a resource to be exploited to our advantage. Dragons look at humans that way.
The "evil" ones will kill us and torture us for sport. The "good" ones will only kill us if we make them, by, for example, failing to turn over all the treasure which they view as theirs. "Look here, little fellow, I don't want to have to hurt you, just be a good little pet and hand over your treasure..."
Gygax clearly has a similar concept, hedging his bets on their alignment, mentioning their "neutral tendencies". For some reason, he elevates the Silver, Gold, and Platinum Dragons as full good and noble beasts.
I think dragons are, as a rule, selfish, voracious, narcissistic, and pompous. They aren't like "big pets", who would respect us or think of us as equals in any way. They think of us as a lesser lifeform, one which has an odd obsession with acquiring their food source (metals and gems).
In other words, they treat us exactly as we treat bees. They tolerate our hives because we produce honey for them. We don't think of the feelings of the bees as we steal their hard-earned honey, nor do dragons consider our feelings as they steal our hard-earned treasure.
This tendency is especially amplified by AZ Adventures being a dawn of civ milieu, with the land being largely untamed. The Gygaxian world of 1e MM is a human-dominated world, everything else hanging on at the edges, or surviving far underground. A certain percentage of dragons there have learned to communicate with humans because humans are the dominant life form in that milieu.
The world of AZ Adventures is not human-dominated at all, except for a few "points of light". Thus, dragons go about their lives in their wilderness domains hardly ever encountering humans, certainly having very few opportunities to interact with them. Thus, in AZ, very few dragons speak our language or have the experience to think of us as equals or superiors.