There does seem to be a pretty thin line between 'Respecting the traditions of another culture' and tolerating atrocities. The Federation didn't intervene on Bajor but they sure showed up and offered their support once the Bajorans had already won.
But I wouldn't be as cynical about this as you, Ghemor. The Federation would not openly tolerate slavery or systems where people are treated as unequal totally based on where they were born. There are several cases where they ignore their political best interest based on values.