Their failings don't remove their achievements.
In the case of Gandhi it's not just the current criteria. Even during his time people saw him as a shitty person. It's good that we stop worshiping great men.
Rabindranath Tagore saw him as a nihilist with fierce joy of annihilation. Many Dalits (untouchables) saw Gandhi as the enemy. While he worked alongside them in some aspects, he was patronizing towards them. Ambedkar said that Gandhi did not deserve to be called mahatma.
Gandhi was monster towards his family. He denied education for his family and tried to force his sons to celibacy. He was against giving his wife penicillin to safe her life for religious reasons and she died. When he himself became a sick soon after, taking quinine was suddenly OK.
Gandhi was a fanatical opponent of sex for pleasure. But just because he didn't do intercourse didn't mean he was not sexually active. For all his celibacy, he had a harem of teenage girls who fought hysterically for the opportunity to sleep naked with him and hold him. Those same girls also gave him his daily enema. He was in today's terminology into 'assplay' and practiced erotic sexual denial with underage girls.