>>>You cannot unconditionally believe everything that is written in books. In this case, these stories probably reflect the biases of the author, Jonathan Rosenblum
The Hebrew book on RSFM, Shlichusa D’Rachmna, written for and by they type of crowd who would not approve of such an haskafa says very similar things. So did a Jewish Observer article written in the 1980s by a talmid of RSFM who remembered him saying such things