I think its important to distinguish between people and attitudes. Pirkei avos says choviv haadam shnivra btzelem, and we should work to refine then as is our halachic obligation with sheva mitzvos bnei noach.
We can despise their beliefs but I don’t think it jives with chazal above and also “lo nitna HaTorah ela laasos sholom baolam,” to secretly despise everyone while acting polite. The Arabs tried that and the secret got out.
Plus it doesn’t seem to enhance any good middos by having this attitude, quite the opposite.