Well, that is great that you later on in life grew strong enough to easily handle your bullies.
For many people that is not an option. Bad example, but look at George Zimmerman. He tried learning martial arts, and after somewhere between 6 and 12 months of trying was told by the school he would never learn it, and was kicked out. It’s probably what started him carrying a gun in the first place.
What the Texas shooter did was despicable, and I do hope he gets the max, but let’s think about this from other angles a minute. If you’re bullied, and unlike your hero on screen you know there is zero hope of ever getting payback with your fists, what is next? A weapon of some sort, like a gun?