I think the interviewing process is an extremely informative view into what it's like to work at that company. The exact steps to take depend on how bad it is / how much you want the job / other context, but I think it's a safe assumption that they are treating you like they treat their coworkers, and that this is not unusual behavior for the company.
I've ended a few interview processes at companies due to things I observed during onsite interviews (not necessarily rudeness), and with the benefit of hindsight I think those were absolutely the right call.
I did have one particularly rude interviewer once, but since it was in finance I thought it was a "stress interview". I took the job, and it turns out that this person was just toxic and the company had a culture of tolerating toxic people if they were high enough performers. I'm still glad I took the job, but the experience definitely was strong evidence of the link between what you see in an interview and what you get if you work there.
I've ended a few interview processes at companies due to things I observed during onsite interviews (not necessarily rudeness), and with the benefit of hindsight I think those were absolutely the right call.
I did have one particularly rude interviewer once, but since it was in finance I thought it was a "stress interview". I took the job, and it turns out that this person was just toxic and the company had a culture of tolerating toxic people if they were high enough performers. I'm still glad I took the job, but the experience definitely was strong evidence of the link between what you see in an interview and what you get if you work there.