Tibbs the butler comes across as a bit of a snob, despite the lowly position he occupies on the social ladder. One gets the distinct impression that he's used to serving the cream of society, the old money elite who know the difference between a Château Lafite and a bottle of cheap Spanish plonk.
That being the case, he finds the prospect of serving the nouveau-riche Cleavers to be something of a chore. The simple fact is that Tibbs doesn't respect them, and he doesn't hesitate in joining with Monsieur Estragon to polish off the extensive collection of wine that Mr. Cleaver purchased at considerable expense.
Tibbs is such a snob that he's convinced that Mr. Cleaver, no matter much expensive wine he buys or how many books he reads on the subject, will never know the difference between good wine and bad. And he's right, because Mr. Cleaver doesn't realize that he's been drinking the “odious” Spanish wine all this time instead of the good stuff.
Even so, Tibbs's snobbery and disrespect towards his employer do leave a rather unpleasant taste in the mouth, rather like a cheap and odious Spanish red Mr. Cleaver has unwittingly been serving his dinner guests all this time.