I think that what Mr. Alford's point was that the Senator was trying to counter his testimony with nothing more than a resolution from the NAACP and some statement from the 100 Men from Atlanta. She wasn't offering any counter evidence, just statements that those two groups made. Because she wasn't offering up any evidence to counter Mr. Alford's factually based testimony, I believe that he was drawing the conclusion that what she was doing was trying to counter him with statements from other African Americans which then means that he can't say anything because they are black organizations.
Obvioiusly, I'm not him so I can't say that that was what he meant, but I would agree with his position. Anyone can pass a resolution or issue a statement, that's not evidence of anything other than the fact that they made a resolution or issued a statement.