This isn't a good example, because this isn't "walking on eggshells", this is an example of a misguided policy that has unintended consequences, and in your own example, when they understood the unintended consequences, they removed this.
Sure, this person was probably bad at their job, and that's problematic, but this isn't an example of someone being fired because they said something non-problematic.
Correct, they didn't remove the policy or change their views on the surrounding context of the disciplinary meeting. They simply understood the issue after it was explained to them. It's not a high bar.
Sure, this person was probably bad at their job, and that's problematic, but this isn't an example of someone being fired because they said something non-problematic.