Excellent and thorough work @cyfung1031
I have forwarded these requests to the developers and they are currently checking if these scripts are still needed for adequate ad blocking on YouTube. Support for scriptlets ( #7362) should be landing in the next release and I expect that these scripts are not at all needed anymore, meaning they will be removed.
In any case, I agree that the user should be able to completely remove these scripts and that disabling the content blocker should do that.