Ehhh, you guys either choose to omit crucial information or really have missed a lot.
Humans are transporting the non humans prisoners to Drakenberg, a hellish torture prison for the non humans. Pogroms everywhere and whatnot. Anything the non humans have done in their rebellion doesn't even come close to what humans are doing on a much larger scale, every day. So much for that.
It's like the Nazis vs Somalian pirates comparison.
Geralt detests politics and King Foltest. They weren't friends. Foltest is an asshole, why would Geralt care if he died? (it's rhetorical btw). All Geralt from the books would care, is to clear his name, and even that one is not a 100%.
You're thinking that the book Geralt, who died protecting the non humans being massacred by humans, would abandon his dwarven friends fighting for a better future in Vergen, to play James Bond with Roche and do politics for the whole second and third act? Goes directly against book lore, and against Geralt's character.
Roche is not Geralt's friend, he blackmails him into helping him find the king slayer. Under that condition, I felt no trust or loyalty towards him. Also, Roche is not a saint, but a brainwashed killer who thinks the service for king and country somehow makes what he does good.
On the other hand, Iorveth, even though we started as enemies, shows honour and integrity, and even goes as far to trust Geralt with the same. If we put aside propaganda and rumors, and judge people based on their action, I'd have to be a piece of shit to just hand him over all tied up to Roche.
At the end of the day, Iorveth may be often blinded by rage and deceived by humans (Letho, Nilfgard), but his end goal is freedom from oppression and a chance for their place under the sun. This he proves later down the track, I don't want to spoil anything.
Roche's end goal is to serve as a spy for his king and country, neither which hold any real value, especially not to Geralt. It gave Roche some sense of meaning and reason for living, being a mindless piece of trash when Foltest found him. How inspiring.
But we can reiterate our interpretations till the end of time, it comes down to personal perception and principles.