My script constructs an rsync command with a --progress arg by default.
I let the user of my script specify rsync args, which I append to the default args.
Without a --noprogress arg, the user can't turn off the default I chose.
I could work around this by recognizing --noprogress, deleting it from the user list and deleting --progress from my default list. Messier, and it also introduces into the user's mind that there is a --noprogress arg to rsync, which there isn't.
I assume you found the --no-progress option (which I note here to make the bug's comments complete). Enjoy!