Sartre advocates something similar to Kant's categorical imperative, but in a secular justified version. Connected also to being condemned to be free is that one experiences the full existential weight of the conditions one has to countenance.
A la. Nietzsche and his 'yea saying', affirmation, with Sartre it becomes a call to eros or eroticism. Every judgment, at the base of humanist thought and principle, has to be resolved erotically. Therefor, when Sartre talked about 'hell being other people', they are the other representations of the species which one has to redeem the judgments thereof. This means that every judgment must be resolved erotically or else one is 'bigoted', to the humanist, which puts the lowest bar standard for 'human' possible into effect.
One becomes inauthentic, then, to Sartre, if one has thymos toward other humans/human beings, if one doesn't submit erotically to his judgments. He reserve thymos for himself and his own confidence in judgment, with no humility: "There is no God(s)." and his imagination of humanism is somehow indistinct from what anyone else imagines - countenancing no differences in capabilities between humans. If a race cannot countenance the ideal like he does, then this presents a problem with them being classified as non-human. Since his sentiments are isolated to his particular ethnic makeup, the resolution of this problem will be the postmodern 'multiculturalism'. The ideals are changed or flexible but the anti-ideals, or the 'evils', are not changed.