I hate my roommates lack of decency
What sort of decency do they lack?
He doesn't keep his bathroom clean & he never washes his dishes. He's kind of living in my house for free.
It's reasonable to be mad at someone who doesn't help out around the house. You should sit down with him and discuss your problems
He must be a hippie brat or something...
It would be good to make sure he knows he should be helping out, especially if he is living there rent free.