This presentation on how communication trough relays work shows why Nostr is censorship resistant. 

nostr:nevent1qqsytl33nwkmnu7dkff2q5wemxwlmv9v5pmg69vcj2v37t96qc5ua0gpzamhxue69uhhyetvv9ujumn0wd68ytnzv9hxgtczyqlhwrt96wnkf2w9edgr4cfruchvwkv26q6asdhz4qg08pm6w3djgqcyqqqqqqgs8gppx