Why did Southerners have a problem with the enforcement of the fugitive slave act?

Southerners had a problem with the enforcement of the Fugitive Slave Act because it allowed for the capture and return of escaped slaves from the South to their owners, even in free states. This led to conflicts with abolitionist sentiments in the North and raised concerns about the legality and morality of slavery. Additionally, some felt that the Act placed too much power in the hands of federal authorities, infringing on states' rights.