From https://en.wikipedia.org/wiki/LIU_Sharks:
The LIU Sharks are the athletics teams representing Long Island University's (LIU) campuses in Brooklyn and Brookville, New York.[2] The Sharks compete in NCAA Division I athletics[3] and are members of the Northeast Conference.[4] The LIU Sharks are the result of the July 1, 2019 unification of the athletic departments which had previously represented two separate campuses of LIU, the NCAA Division I LIU Brooklyn Blackbirds and the NCAA Division II LIU Post Pioneers
The Brookville campus apparently was originally CW Post University.
I guess they're filling a void created by Hofstra dropping football after 2009, who was somewhat of a power in I-AA.