Normalization is a legitimate, effective, and popular technique employed across the entire entertainment industry. Most well produced audio will have degrees of the effect applied tastefully.

I have no idea what youtube’s “normalization” is doing that ruins the quality of their audio to such a noticeable extent. It’s also totally indiscriminate of the video’s existing audio production. It sucks for someone to work hard and produce a good mix only for youtube to ruin it without your consent, possibly years after release