Sorry, but two nurses is hardly enough to generalize about ER nurses as a whole.
They shouldn't have been rude to you. Also consider that the ER is a very stressful, fast-paced environment, and there were probably a lot of patients sicker than you and your friend. The priority in ERs and critical care units keeping patients safe and alive. Unfortunately, that means sometimes nurses and doctors are rushed.
You're generalizing based on one experience. That's unwarranted.
But yes, ER is a stressful place and it's the nurses (not the doctors) who bear the brunt of dealing with often unreasonable, unruly (and just plain nasty) patients. They probably were "having a bad day." That may not be an excuse, but it happens. I have a relative who's an ER nurse and she has told me some amazing tales of what they deal with.
ER nursing is very stressful and the job is demanding. They usually have more patients than they can handle and do the best they can.
They see the most crisis situations and can't give the little things as much priority.
They are there to save lives, not to make nice.
Never met one who was?