^ IIRC, we never learned *why* the Andorians were supporting the Coridan rebels. Could be they just wanted the dilithium mines and the shipbuilding facilities (plus a chance to really stick it to the Vulcans, which is even more likely).
In any case, this is hardly a "history". The Andorians supported the Coridan rebels, yes, and helped Earth against the Xindi. But that doesn't exactly make a pattern.
But it's the only canonical data we have about Andorian policy towards less-powerful worlds. If the only data we have is two instances of them taking risks to help less-powerful worlds and no instances of them refusing, then at the very least we must concede that there's no reason to think they would
refuse to help Earth, even if we don't think those instances are enough to be evidence they
would.
That kind of decision has to have been authorized by the government back home, because it would be incredibly dangerous for the Andorian Empire to make enemies of the Xindi if the super-weapon survives.
Well, to be fair, Shran doesn't really seem to care what his government thinks.
Evidence? I can't think of any episode in which Shran indicates he doesn't care what his government thinks.
He could have simply decided on his own to help.
No way. You don't rise to become commander of your world's flagship if you're willing to plunge your planet into a war against a race so much more powerful than your own. That kind of irresponsibility simply wouldn't happen -- and if it did, Shran would have been removed from command immediately afterwards.
(As for the Xindi: they hated humans so much specifically because the Sphere-Builders told them to. There's no evidence they would have tried to wipe out Andor like they did Earth.
The Andorian government does not know that. From an Andorian perspective, there is a significant probability that going into combat against the Xindi Super-Weapon in defense of Earth would lead to Xindi retaliation against Andor if the allied fleet fails. If you're the Presider of the Parliament Andoria (the name of the Andorian head of government in the novels), it is your responsibility to assess risks in those terms, not to just assume your world is safe if you make a move against such a powerful species.
And even if they did - the Andorians had a much stronger military, they'd be ready for them.)
I mean, the Andorian Imperial Guard is stronger than the United Earth Starfleet, but there's no evidence that Andorians have the kind of technology needed to blow up a planet. Indeed, if they did, they wouldn't have tried to steal the Xindi weapon early in ENT Season Three. Going into open combat against the Xindi represents a
significant planetary security risk for Andor.
But getting back to the Earth situation: Like I said, what would the Andorians likely think of Earth as it appeared in ST:FC? A weak, defeated, bombed-out wasteland, with no strategic importance, and no clear victor in the war that happened only 10 years prior. Why would the Andorians be particularly impressed with that? What would Earth have to offer them?
That line of thinking could be applied to
any species that makes contact with post-WW3 Earth -- including the Vulcans and Denobulans, who we know
didn't assess Earth only in those terms.
There is absolutely no reason to think that the Andorians would not feel altruistic towards a suffering Earth -- and there is evidence that they might feel altruistic. Being a violent race does not preclude that.
Hell, you remember how Shran initially tried to steal the Xindi prototype and take it back home, specifically because the Andorian general ordered him to? That's as much an indication of official Andorian policy as anything else.
Sure. It's an indication that when the Andorian government became aware of a race with technology that gave them the potential to pose an existential threat to Andor, that they wanted to have such a weapon themselves. (The equivalent of other nations like France and the United Kingdom wanting to develop their own nuclear weapons program after the United States dropped the atomic bomb.) It tells us absolutely nothing about how altruistic they might be to less-powerful races.
ETA:
And, again, let's not forget that the Andorian Empire was one of the founding member states of the United Federation of Planets. This is not insignificant, and cannot be attributed to the influence of just Shran. One guy cannot influence and entire society to such an extent, particularly someone who is only a starship commander and not the leader of a major social movement of some sort. If Andor helped create the Federation, then it must have already developed a political culture that embraced certain Federation values like freedom, universal rights, and social justice.