The hedge fund manager Daniel S. Loeb, a prominent supporter of charter schools and a major financial backer of Gov. Andrew M. Cuomo and congressional Republicans, accused the African-American woman who leads the Democrats in the New York State Senate of having done “more damage to people of color than anyone who has ever donned a hood.”

Mr. Loeb made the reference, apparently to the Ku Klux Klan, in a posting on Facebook in response to an article in The New York Times this week in which the Democratic leader, Senator Andrea Stewart-Cousins, confronted Mr. Cuomo about prejudging her based upon race and gender.

In a private meeting last month, The Times reported, Ms. Stewart-Cousins said to Mr. Cuomo during a debate over who best understands suburban voters: “You look at me, Mr. Governor, but you don’t see me. You see my black skin and a woman, but you don’t realize I am a suburban legislator.”