You can find more information on this topic by taking a look at this post. In short DFINITY operates Boundary Nodes using the icp0.io and ic0.app domains and maintains a content filter for these domains pursuant to the terms of the Code of Coduct. However, this filter only applies to the HTTP endpoints, allowing other gateway providers and IC-native clients “unfiltered” access to the IC. Any community member can set up and run a gateway using their own domain and define their own policy.