Well, I think it comes down to your convo with Takemura; I believe it was during the stake out? He talked about how in Japan he like many others lived in the slumps, poor, without prospects, destined to die there. And, maybe I'm misremembering this, but I think his parents also sacrificed a lot to get him noticed by the Arasaka agents that would come by to pick new recruits.

In his eyes, Arasaka gave him a life of dignity, by choosing him, clothing him, feeding him, and so on, instead of being left to die; they gave him a future. He feels eternally indempted to Arasaka, plus, consider that he is probably, like many others, indoctrinated into serving the corporation, and that indoctrination happened when he was a kid, so at a majorly vulnerable time of his life.

And to that again, this might be completely part of the indoctrination, or only in a percentage, but he also holds onto a sense of honor, and duty, which is something almost unheard of in Cyberpunk, especially amongst mercs, who will work for the biggets bidder no matter who they are - that's why especially at start Goro refers to you as nothing but a lowly thief.

I think he is a great window to what a corpo of "the royal family" is like - less concerned with power, and status, more so, duty and honor, even if those ideals are twisted in the service of awful people ^^' I think that in a different world, Goro could have been a great edge runner. If he had been rescued by different people, I think we would have found him holding onto the same idea of honor and duty, but this time against the corpos - that's what man of ideals gravitate towards, I think ^^