In Cogenitor, Starfleet wouldn’t get very far if it had to roll up to every first contact demanding a species conform to human morality. It has to take a neutral position or first contact becomes an ultimatum. That doesn’t mean Starfleet is pro-slavery, it just means it recognizes that it’s not in a position to force that change on a species it met five seconds ago. Now if the species was trying to join the Federation (down the line) obviously that’s a different story…

The Orion episode too… Uh, weren’t the “slaves” actually just pirates? Can we trust anything said when it was just a setup to steal the ship? Not to mention that just because a character says something doesn’t make it true or reflect the morality of the show/writers. Maybe that Orion is just an idiot or rationalizing his shitty behavior…