I think the birth of Hitler is an easy choice. But I wouldn’t be surprised to learn that eliminating some earlier event could both right another wrong and negate Hitler’s existence.
Aside from that there’s the existence of the internet, which I’m not sure has been an overall benefit to humankind. I think about this often.
Further, nobody willingly leaves the military at 19 years. 20 years and you get retirement pay for the rest of your life–19 gets you nothing.
Maybe he had a medical retirement, which is fully possible for any number of reasons, but…
Probably he did something egregious to get kicked out at 19 years. Leaders will often let servicemembers near 20 years retire when they’re guilty of wrongdoing (in consideration of the many years served beforehand). To cut short a retirement career is to make an example of a person for doing something awful.
Edit: He was still active duty and stationed in Germany, making my whole comment moot. My bad. That’s what I get for not reading the article before commenting ¯_(ツ)_/¯