How do I access all the public folders?

I am not sure if I understand your question. This sounds like a bad thing to do, because you are introducing a very insecure environment.

The issue is with the security of the computers, not the network. Each individual computer specifically prevents people from accessing data over the network because people accessing your data over the network is usually a bad thing.

This is why there is an opt-in policy where specific drives are made "public". What you want to do (if I understand the question correctly) is make the entire drive public.

Of course, you can't do this unless you have administrative access to each of the individual computers in question.