In favor of freedom of expressing
I would not like to see Librarians become censors, in the guise of opposing "fake news." I would oppose Librarians becoming like Google and Face Book: Google manipulates Internet search results and Face Book cancels accounts, and it is "left" leaning sites which have been targeted. The Constitution of the United States guarantees freedom of speech and freedom of the press.
Librarians should never let themselves be placed in the position of deciding what is "fake" and what is "true," or what is accurate information and what is "disinformation." That is not the Librarian's role. Every subject under the sun is controversial.
So, to answer the question posed in the Forum, what can Librarians do?
I think this is the time to strengthen the traditional role and responsibility of the Library, helped along by the digital technologies. I also think we need a vigorous culture of peer reviewing and book reviewing, encouraging intellectual debate and discussion. This is also the time to strengthen and renew the "Library Bill of Rights" for the information age.