It's totally understandable that the Bachelor is dismissive about the superstitious practices of the steppe/town. He's a rational man of science and there's no time to waste in the face of a catastrophe. It's normal/best to assume that ridiculous, unfounded ideas are false until the evidence shows otherwise.

But even Bachelor admits that there's some value in the steppe medicine when he starts working with Haruspex. He was also amazed that the kids' ridiculous mixtures (shmowders) seemed to cure the sand pest but he accepted it. I think this shows that he's ready to change his beliefs when there's evidence.

In the end he's also respectful towards Haruspex and tries to use steppe honorifics by calling him Oynon. The fact that Bachelor is rude sometimes is not a big deal when there's a big catastrophe. He probably believes that he must be assertive to get things done. I don't think he's any more flawed than the other main characters.