People who kill there kids isn't something that is super rare. There likely is another reason for why that case, in particular, becomes so famous. I'm not going to spend hours researching into the case, but after a quick search I found a random article talking about the topic.
Source
The circumstances of the case seemed to be what made it so popular.
These school shooters are typically young, male, social outcasts who have little to no friends. If you have someone like that who wants to become infamous, what is the easiest route?
A.) Working towards having a kid, kill the kid, bury them in your backyard, have a family member report the kid missing, leave little hints towards the fact that you have a dead body in your yard, have a long, drawn out trial on whether or not you murdered your kid (and it still likely wouldn't get much attention, since they aren't attractive women).
or
B.) Get a gun......and shoot up a school.
At this point, I'm just going to assume you aren't taking this serious and are trying to waste my time because these replies by you can't be genuine.