core-rsync does not accept multiple --exclude options

In my local environment, I don't want to copy uploaded files like pdfs, mp3s, etc but I do want uploaded jpgs so nodes with images will not show broken images after grabbing the remote database. I'd like to build a list of patterns that are excluded in my drush aliases to save time from transferring undesired files. My previously posted issue shows how I was able to include a list of patterns via rsync --exclude-from=/path/to/file, but I wanted to use that on a server alias and then have site-specific excludes in another alias, I would only be able to pass one of them through drush.

The help pages for drush core-rsync state that --RSYNC-FLAGs will be passed onto drush's command, but if you use multiple --excludes only the last one is used.

$ drush -v rsync --exclude=".htaccess" --exclude="*.pdf" @proj-trunk:%files @proj-local:%files
...snip...
Do you really want to continue? (y/n): y
Calling system(rsync -e 'ssh ' -CrlptDzv --exclude="*.svn*" --stats --progress --exclude='*.pdf' alan@devsrv:/var/www/vhosts/project/sites/default/files/ /Users/alan/Sites/project/sites/default/files)
...snip...
Command dispatch complete

This is because of the way rsync flags are whitelisted in rsync.core.inc, right?