There are doubtless many reasons why this may be so, starting with the contention that the analogy is invalid. Nevertheless, not only is snobbery not universally abhorred, it almost seems to carry a cachet of approval.

Should we then conclude it is okay to look down on our fellow men because of socioeconomic conditions, but not because of accidents of birth? Even though those socioeconomic conditions may be just as accidental?

Deriding those in other socioeconomic classes happens in both directions, with similar acceptance.