Antonyms for the phrase "sings the praises of" include words such as disapproves, criticizes, condemns, censures, defames, belittles, and denounces. These words all convey a negative connotation toward the subject being discussed, rather than expressing admiration or approval. When someone is singing the praises of something, they are usually highlighting and celebrating its positive aspects. Conversely, criticizing or condemning something implies a negative opinion or judgment. While there may be occasions where criticism is warranted, it is important to approach it with a measured and thoughtful perspective, rather than being overly harsh or unfair.