The narrator does try to be understanding of Bloch.
I did not believe what he was saying, but I bore him no ill-will on that account, for I had inherited from my mother and grandmother their incapacity for rancour even against the worst offenders, and their habit of never condemning anyone. Besides, Bloch was not altogether a bad fellow: he was capable of being extremely nice. (II, 445)
But he tires of the effort. Bloch is at Balbec with his tribe.
Personally, I was not particularly anxious that Bloch should come to the hotel. He was at Balbec, not by himself, unfortunately, but with his sisters, and they in turn had innumerable relatives and friends staying there. Now this Jewish colony was more picturesque than pleasing….they formed a solid troop, homogenous within itself, and utterly dissimilar to the people who watched them go by and found them there again every year without ever exchanging a word or a greeting…(II,434)
Marcel and Robert are invited to dinner with Bloch and his family and witness scene after scene of vulgar behavior. Here is Bloch’s father scrimping on the wine and theater seats.
However, if the failing of his son, that is to say the failing which his son believed to be invisible to other people, was coarseness, the father’s was avarice. And so it was in a decanter that we were served, under the name of champagne, with a light sparkling wine, while under that of orchestra stalls he had taken three in the pit, which cost half as much, miraculously persuaded by the divine intervention of his failing that neither at table nor in the theatre (where the boxes were all empty) would the difference be noticed. (II,487)
And in the unkindest cut of all, Bloch is revealed to have had sex with Odette in a railway car.
“I picked her up a few days before that on the Zone railway, where, speaking of zones, she was so kind as to undo hers for the benefit of your humble servant….I was hoping ,” he said, “thanks to you, to learn her address, so as to go there several times a week to taste in her arms the delights of Eros, dear to the gods; but I do not insist since you seem pledged to discretion with respect to a professional who gave herself to me three times running, and in the most rarefied manner, between Paris and Point-du-Jour. I’m bound to see her again some night.” (II,489)