Alexander the Great?

Question

did he go against his Greek ideology?

Answer 1

Certainly not. He conquered almost to the border of India, and everywhere he went, he founded new Greek colony cities to propogate Hellenic culture. Also, he was not Greek: He was Macedonian. He had Aristotle as his tutor.

Answer 2

Hardly, as the Greek state at around 336BC did not exist as an entity, more a loose confederation of occasionally warring city states, (like Athens, Sparta and Thebes) that sometimes united against a common foe like the Persians.
Alexander did what many great leaders over history were often forced to do, to conquer and subjugate his own people in order to unite them before embarking on military conquest abroad.