We suggest firstly that you determine whether the non-Muslim made this statement as a criticism or merely as a personal opinion based upon misinformation gleaned from the media and other sources.
In the case of the former, the best is silence if you feel that no amount of convincing proofs will get you anywhere. In the case of the latter, ascertain which part of Islam he is referring to and respond accordingly.
and Allah Ta’ala Knows Best
Mufti Muhammad Kadwa
FATWA DEPT.
CHECKED AND APPROVED: Mufti Ebrahim Desai