Is it normal for someone in their 30s to NOT be financially helping their parents?

Short answer:
Yes.

Long answer:
Are you a $millionaire or $billionaire? You should be financially helping your parents if money is a problem for them. If you are not a $millionaire or $billionaire? Then see my previous answer.

If you are able to financially help support your parents and they are incapacitated in some way, I am not sure why you wouldn't want to help them.

In my late thirties, I chose to financially support my mother due to the fact that she was struggling with personal issues and could no longer afford to support herself financially. I still support her in this capacity. I am not rich by any means.

The other alternative, well, not sure there is one. I suppose I could let her be homeless or figure out how to support herself in her mid-70's.

Of course it is. If your parents have got it together financially, then they don't need help.

Are your folks trying to make you feel guilty for not handing over $$?

If you are in your early thirties, your parents should be in their high income years, when the kids are out of the house and they are well established in their jobs. In most Western cultures it is generally an unusual situation if the children are supporting the parents. Maybe not so much in other cultures.

Yes.