I have heard that it is not permissible to wear a Jinnah cap.

Answer

A Jinnah topi is the headgear of fusssaq. It is not permissible to emulate the fussaaq nor to adopt their dress styles. Mufti Taqi's commission of an act of fisq does not alter the law of the Shariah. When one mingles with fussaaq and fujjaar, one's Imaani inhibition to fisq and fujoor becomes eroded. One then becomes desensitized – spiritually paralyzed which renders one incapable of understanding Shar'i realities.