Earlier quoted context omitted.
You're straw-manning. The suggestion was that it would be useful to have a best-effort system to try to detect when people make mistakes. I don't think there's any suggestion that it should be something that people rely on, or that the system should or could be perfect - merely that it would be useful.
I wouldn't go so far as saying I was creating a straw-man argument. My point is just that relying on other people to take care of security for you ends up with an "eh" attitude in the long-run, and self-education is more important. Yes, Github can/should help, but developers should not think they're owed it just because they constantly check in sensitive info to a website, that's all.
(I'm just applying your point to another kind of 'security' that is provided to you).
You are basically arguing the "We should all live in the woods, and hunt and kill our own food, because relying on other people is fraught with danger" line.
Or we could accept mistakes are made, and provide warnings/undos/etc. Kind of like how cars have airbags, even though they are rendered moot by just "not crashing your car"