Most of the dialog was recorded live with a boom mic, whereas all the singing is either lip synced or ADR. The exception being Rex Harrison whose singing was all done live on set and thus perfectly in sync.
You are misquoting him.
Exact quotes are helpful! :DHDR is the culprit and a 4K Blu-ray with that same HDR grading would also be compromised. I don’t believe RAH has anything against streaming, he just wants complete transparency to the original file and today’s streams aren’t quite there yet...