Reading religious information is not a disfellowshipping offence. Bethel and the branches have religious texts in the library that can be read by the bethelites.
I started researching various religious groups whilst at Bethel, and had some free publications posted to me. I asked Don Maclean, one of the branch committee if that was ok, and he said it was fine. He did wonder why I would want to, when the Watchtower and Mankind's Search for God book provided all the information on other religions that I would need. He also warned against spending excessive time look at information not by the Watchtower.
Being disfellowshipped would result not from reading other information, but starting to raise questions about the accuracy of Watchtower information, which is a natural result of research.