well I was assuming that there was some concern that substitutions would happen instead of downsampling so by having standard downsampling options written into the protocol substitution cannot take place, just downsampling and then bloom or whoever who only want to propagate originals can chose the non downsampled version as one particular choice offered by the protocol
Discussion
If you want to ensure integrity of the content, use content hash and not bit hash. Downsampling is not the only way to make things better, there are hundreds of ways and it is not practical to mix them into the protocol 🐶🐾🫡