I understand your point--I write for a community newspaper that was established to help fill the void caused by more traditional news sources closing. My point is that newspapers that cover elections have a responsibility to help educate the voters on the candidates. I obvious wish the papers in Long Island would have exposed Santos' lies before election day.
I fully agree with you that many local newspapers and even TV stations lack the resources or staff to research candidates. I would note, however, that while I am not familiar with how the NYT uncovered the fraud, the research would have been quite simple--colleges will acknowledge whether or not someone graduated. Similarly, Citigroup and Goldman would have responded to a press inquiry, I think, had they been asked whether Santos ever worked there.
In any case, thanks for raising your point.