The difference is that I know that written articles can be changed with no notice. I did not know that youtube videos can be edited like this.
Youtube did not do that in this case. I would not have had any issues with this if they had indicated that the content had been altered.
The reason google doesn't allow you to change it in-place is problaby to avoid "selling" of popular youtube videos to be replaced/injected with ads.
The ability to stealthily rewrite history is a major issue.