Scott When it comes to security, details matter. When specific concerns are raised about F-Droid, those concerns may or may not apply to unrelated projects.
Debian was one of the distributions targeted in the xz attack. The outcome for them was ok, but that was partly luck.
Overall, "Debian does X" does not necessarily mean it's right, and "F-Droid does something like what Debian does, at a high level of abstraction", does not mean F-Droid is right.