rsync can not delete .git/objects directory files

You would be ok with a script that first changes the permissions. It could work on specific directories or on all .git/objects in a (sub)set of directories.

Taking as an example the command line you posted in the question

rsync -ab --delete-delay /media/blueray/WDRed /media/blueray/UltrastarDaily 

and naming rsync_my.sh script below,

#!/bin/bash
TARGET="${@:$#}"   # last parameter
SOURCE="${@:(-2):1}"   # second to last parameter
TARGET2="${TARGET}/$(basename ${SOURCE})/_Working/_NotesFiltered/
for d in $(find ${TARGET2} -type d -name .git) ; do 
    chmod -R +w $d/objects
    for d2 in $(find ${d} -type d) ; do
        chmod +x $d2
    done
done
rsync "$@"

you would execute

$ chmod +x rsync_my.sh
$ ./rsync_my.sh -ab --delete-delay /media/blueray/WDRed /media/blueray/UltrastarDaily 

The first command is needed only once. SOURCE would be /media/blueray/WDRed and TARGET would be /media/blueray/UltrastarDaily. Please test it and post feedback. To test, you could

1. Put together a dummy directory/file structure with some 10 files that replicates the essential structure of your target dir, and execute the script.
2. With rsync, use option --dry-run to only see what would be done, and create a log file that you can later inspect with --log-file=mylog.log.

Parameter expansion/extraction may need fine tuning.

Related:

1. https://stackoverflow.com/questions/41382232/git-objects-directory-contents-make-git-set-the-write-permission-instead-of
2. https://stackoverflow.com/questions/6448242/git-push-error-insufficient-permission-for-adding-an-object-to-repository-datab/6448326