iirc the debate is basically Janeway insisting that her timeline must be preserved at the expense of people in the 90s, while Starling's position is that his present is more important than a future that, from his perspective, hasn't happened yet.
I don't think either of them are wrong, both have a duty to do what's best for the people in their own timelines, that duty just puts them at odds. Having said that, I don't remember it too well; I haven't rewatched it much precisely because I remember finding the script's black-and-white view unconvincing, and the "haw haw haw, i will annihilate LA to prove i'm evil" generic corporate bad guy trappings just render the whole story dull in a way it didn't have to be.
Stirling's position was all about greed. His own personal gain and nothing else. The man wasn't concerned about providing society with anything. Nor did he give a crap about "duty". And I'm confused at this idea about Janeway insisting upon preserving the timeline at the expense of people in the 1990s. How did you come up with this?
Meanwhile Starling is personally planning on doing something very risky and dangerous to get advanced technology from the future to profit himself. He's already plenty wealthy from the tech he stole from Braxton. He doesn't need more. He's not even planning on giving the future tech away as an altruistic act. When people from the future tell him this is a very bad idea, he says he doesn't care and tries to do it anyway. That's evil.
This is Henry Stirling in a nutshell.