"There have been comments by PCAs and nurses about new grad nurses not knowing something." Well, yeah--they're new! People who criticise others for being new and not knowing things, in my opinion, need to step out of their situation and remember that they were were new at nursing/assisting too. Although it may hurt to hear those things, please remember that it is not a reflection on you but on them.
It's hard to know what she meant--if she was advising or intimidating, but it sounds like you felt vulnerable.
It also sounds like you feel afraid to be honest and transparent, and that is never a good sign.
I can't speak to other hospitals and whether other nurses treat students this way but I'm sure there are and as others stated, it's on an individual basis. I personally have always loved having students. I've had such great preceptors in the past; I feel that desire to impart the awesome knowledge handed down to me.
I am going to step out on a limb and assume things about these nurses at the hospital that you work at and say they sound unhappy. Unhappy, stressed out, probably angry and feeling a bit helpless. But that doesn't give anyone license to be rude and mean to others. I hope things improve for you.