It’s a little like buying a Lamborghini, and then speeding and totaling it, and then complaining they need to make it not as fast so you can’t do that.
Let’s say you didn’t know you had to take your new car in for an oil change? You ignore the warning lights and requests to service the vehicle. When the vehicle breaks down, I think it’s obvious that the car manufacturer can’t be responsible for fixing it for you.
To me, this is the same. The computer is functioning exactly like it should, locking him out is a feature for the vast majority of users, requiring some very basic knowledge to prevent/fix (as mentioned in my other comment, it’s hard to have what happened to him happen without circumventing security on the mac)