She is always finding fault with other people.
FYI: There are some synonyms you may want to memorize.
非難 – 非 means “to blame” and 難 means “difficult” or “troublesome”. So, 非難する means "to accuse someone of misconduct or bad mouth.
批難 (also pronounced as ひなん) – 非難 is the proper Kanji, but some native speakers are confused to use 批難 instead.
批判 (ひはん) – 批判する means “to criticize”. 批 means “to make a judgment and to rectify”. 判 means “to distinguish A and B”. So, the original meaning of 批判する WAS “to distinguish good and bad or truth and false” in the past. But we use 批判する in the modern contexts as “to criticize”. There is no significant difference between 批判する and 非難する, but I personally feel 非難する is more subjective or from one’s emotional viewpoint whereas 批判する sounds more objective and is based on rationales.
批評 (ひひょう) – 批評する means “to give a critical review on a subject”. It doesn’t necessarily involve accusation or condemning. 評 means “to analyze and evaluate”. So, 批評家 is a critic of (movies, literature, social trends etc.) 批評する is usually done by experts, so 批評する sometimes sounds a bit snobbish.