Why in the world would a judge dismiss charges against a man for sexual assault because he was found not competent to stand trial?

Recently this guy was arrested for cracking the skull of an 8 year old girl and raping her. But that wasn’t his first sexual assault. In 2017 “Madden was ruled mentally incompetent in February by a judge who dismissed charges the man sexually assaulted a woman and bit off part of her face…”

Well, he’s no more competent now than he was then so do they just turn him loose again?