But still, I also share the opinion that GitHub's UX for dangerous actions on a repository is currently already best in class, so blaming them for your mistakes is pretty unfair. To make your repo private, you have to:

- click "change visibility" in the "Danger Zone" area of the settings.

- select "make private" with an additional warning shown that you will lose all stars and watchers. Ok, maybe it should mention how many.

- type the name of the repo into a box and then click "I understand, change repo visibility".

And yes, sometimes it is important to expect humans to not make mistakes. For example, at railway crossings. Even if you drove over it 100 times and no train came, the 101th time you may still die if you don't check for a train before crossing.