Again, it all depends on how much you trust the third party compared to how much you trust your distro provider. I don't have many third party PPAs installed on my computer because there aren't many third parties I trust that much. But there aren't zero either.

Also, a big part of my trust of my distro provider is based on having source code forced to be open, and another big part is based on them not doing things behind my back. Snaps significantly erode both of these aspects of trust.

Perhaps we should consider why this is: because people want up-to-date software on their computers (desktop or server), instead of being beholden to whatever version distribution maintainers have decided you can have.

I didn't; the post you were originally responding to (the GP of my original post, which is the GP of this one) did. I am not the person who made that post.

You appear to be saying that you can audit, hold, modify, pin software in third-party repositories. That means you agree with what I was saying in the GP to this post, that you have just as much ability to do all these things with third-party repo software as you do with software distributed using snaps.