I think there's some truth to Eddington's analysis of the Federation. "They want to assimilate people, but they don't say it." They want to make people "Normal, like them".
But, they do it always by influence and never by coercion. As Odo says "The Federation has its flaws but the desire for conquest is not one of them".
The Federation's ideals are not to be completely neutral in the fate of the universe. They want to make friends with anybody and they say 'You can join our super-beneficial community but you can't have civil wars or slavery'.