Why other benzene derivatives do not undergo nitrosation
Anisole can be nitrosated in good yield reference here.  This, and other references, note that the PhOMe group is unstable to the reaction conditions being cleaved to give phenol.

m-Xylene can be nitrosated in good yield, o-xylene and toluene in modest yield in TFA or sulfuric/acetic acid mix under nitric oxide reference here

Nitrosonium tetrafluoroborate will also nitrosate a range of electron-rich aromatics, including anisole and xylenes reference here 

This suggests to me that the authors of the textbook quoted are in error, as two of the references predate the publication date of the textbook.