I find people who agree with me for the wrong reasons to be more problematic than people who simply disagree with me. After writing a lot about why free software is important, I needed to clarify that there are good and bad reasons for supporting it.
You can audit the security of proprietary software quite thoroughly; source code isn’t a necessary or sufficient precondition for a particular software implementation to be considered secure.
You’re not the first person to ask, which is why I updated the post to expand the acronym in the first sentence. Diff.