Piracy, or other objectionable content, is not exclusive to P2P platforms. YouTube has moderation features and so does PeerTube. From the FAQ:
Being free doesn’t mean being above the law! Each PeerTube hosting provider can decide on its own general conditions of use, abiding by their local laws.
For example, in France, discriminatory content is prohibited and may be reported to the authorities. PeerTube allows users to report problematic videos, and each administrator must then apply its moderation in accordance with its terms and conditions and the law.
The federation system, for its part, allows hosts to decide with whom they want to connect, depending on the types of content or the moderation policies of others.