וַיֹּ֣אכַל וַיֵּ֔שְׁתְּ וַיָּ֖קׇם וַיֵּלַ֑ךְ וַיִּ֥בֶז עֵשָׂ֖ו אֶת־הַבְּכֹרָֽה
Rashi comments: העיד הכתוב על רשעו, שבזה עבודתו של מקום The Torah here testifies for us that Eisav despised avodas Hashem.
We just read that Eisav sold the bechora for a pot of soup. The act speaks for itself-- why do we need additional testimony to confirm for what should be obvious to any bar bei rav!? (see Sifsei Chachamim)
Furthermore, why is it only after Eisav eats and drinks and marches off that the Torah now comes and testifies that he despised avodah -- don't we know that from the sale itself?
In kids books on the parsha Yaakov is depicted as the super-righteous little tzadik while Eisav looks like the bummy kid who hangs out on a street corner. Were that the case, then Yitzchak would have never made the mistake of wanting to give a bracha to Eisav. Chassidishe seforim say that to our eyes Eisav would look like a rebbe who is ready to say torah at shalosh seudos. Eisav had tremendous kochos, and when we dedicated himself to using them for mitzvos, like the mitzvah of kibud av, his deeds were unparalleled.
Eisav understood that the bechora is a tremendous gift in ruchniyus, which is why Yaakov bugged him on more than one occassion to sell it. But Eisav also understood, as Yaakov told him again and again, that this gift carried with it a tremendous responsibility and was filled with tremendous danger. A mistake in avodah can prove fatal. So the question Eisav asked himself day in and day out, as Yaakov never ceased reminding him that his offer was on the table, was whether it was worth it -- i.e. in the grand scheme of things, was the risk worth the reward? And finally, one day after he came in from a long day out in the field, faced with overwhelming hunger and a fresh pot of soup on the stove, Eisav made his decision.
R' Baruch Sorotzkin explains that had we not had the final pasuk in the story, we would not have necessarily faulted Eisav. He made a cheshbon -- he weighed the risks vs the reward -- and although we may say his cheshbon was wrong and he miscalculated, and we may think he underestimated the incalculable value of bechorah and avodah, we can at least hear the sevara going through his head and understand where he was coming from.
What tells us otherwise is Eisav's reaction after the fact. When a person faces a life changing decision, something that he agonizes over and thinks deeply about, even after he comes to a maskana, he doesn't get up and do a dance afterwards. Hard decisions weigh on a person even after they are made. וַיֹּ֣אכַל וַיֵּ֔שְׁתְּ וַיָּ֖קׇם וַיֵּלַ֑ךְ -- if after the fact you just quaff down a meal and march off without a second thought, then you may tell yourself that there was a cheshbon, you may create all kinds of rationalizations to justify the decision, but those just are just a cover story for what really is in the heart. וַיִּ֥בֶז עֵשָׂ֖ו אֶת־הַבְּכֹרָֽה -- that was the real motivation, and all the rest was window dressing.
That's how it is with so many calculations that we make on the individual level and on a communal level. We pretend to weigh this factor against that factor, we pretend there are all kinds of important cheshbonos going on, but at the end of the day, in our subconscious at least, we already know the answer we are going to get -- the answer we want to get -- before going through the whole charade of deliberation. It takes tremendous amount self awareness to see through that.