Who couldn't like a Zoidberg story? This is my favourite of the 3 main Zoidberg plots (Why must I be a crustaceon in love, That's Lobstertainment, A Taste of Freedom) as it pokes much fun at the contradictory Freedom Day. Zoidberg's people actually declaring war on Earth was a bit much but still worked very well, and the chicken lawyer comes into the episode aswell, always a hilarious character. Zoidberg's mother's lectures were fantastic about becoming a doctor, not a comedian and then going back on it "What, and give up your dream of being a comedian?"
This episode isn't my favourite from season 4 but it is very good.