Can they order supervised visitations?

I was ordered supervised visitations, ordered to go to parenting cl, my parents home has to be investigated, ordered random drug testing and was denied joint custody for my baby girl. I am a good father and always have been. I have no prior record and have no history of any type of violence/abuse. Are there guidelines the courts have to follow to order supervised visitation or can they do what they feel is right? They based the decision on the fact that the mother said I get frustrated when the baby cries...is that enough to slander me like this?