I don't really approve of using 'for their own good' to justify conquest, at the same time, I note that very few people tore down their aqueducts or ripped up their roads when Rome's fist vanished.

In this particular context, I don't see Rand's actions in Arad Doman, or his previous essentially identical but more successful action in Carheinen as unjustified or immoral in any particular way. Nor his subsequent retreat as immoral, just tragic. But the specific morality of his actions, or British Imperialism, is another matter, it isn't 'evil' by any moral compass I can think of. As to the other points, nuking Graendal seems entirely rational and ethical.

I don't think we can call the borderlanders invaders, they were permitted by the soveriegn of Andor to cross Andor, and I don't recall hearing that Far MAdding had either objected to their presence or was Rand's territory. Though their behavior is hostile, moving troops through neutral countries with their permission is not by itself cassus belli, especially when the nominal invaders are waving a parley flag.