Gandhi was stubborn in his tireless advocacy of peace and non-violent resistance. In the face of British colonial rule, this proved to be an effective strategy. However, in the face of true evil, such as that of the Nazis, it proved to be somewhat less so. Gandhi's rigid attachment to his pacifistic principles meant that he had nothing whatsoever to say to the Nazis' victims, most notably the Jews of Europe. His message of passive resistance was completely inappropriate for those caught up in the midst of a systematic campaign of genocide.
Gandhi notoriously said that Jews should willingly go to their deaths in the concentration camps as "martyrs" to their religion. Had Gandhi's advice been followed, the entire Jewish people in Europe would've been annihilated, ushering in a dark age of terror and repression.
Other equally unsavory characteristics of Gandhi include racism. While working as a lawyer in South Africa, he expressed opinions about black people that were truly disgraceful, even by the standards of the time. Gandhi also had no hesitation in expressing admiration for murdering dictators like Hitler and Mussolini. And to his undying shame, he even urged women not to resist if a man should try to rape them.
In evaluating Gandhi, as with any historical figure, it's important to get as much information as possible from a variety of different sources to obtain a more balanced picture. This is all the more important in Gandhi's case as his standard portrayal in the history books as some kind of modern-day saint doesn't match up to many of the things he said and believed.