Goodwill does provide a great deal of employment to people who are physically and mentally handicapped. It is likely asking too much to ask a mentally handicapped part-time employee to recognize your sensitive info and react accordingly.
I agree, they are placing way too much blame on Goodwill and not enough on the lazy people donating, who can’t be bothered.
Expecting Goodwill to sift through it because you're lazy is ludicrous.