Because this has nothing to do with home schooling. The guy was 24 years old. How is home schooling pertinent (other than as a liberal “narrative”)?
It's potentially pertinent if the "why and how" of the homeschooling decision has anything to do with how he turned out. I'm guessing that his parents (described as very, very religious) made the homeschooling decision out of fear of what "the world" would do to their boy. If he was unstable to begin with, and they pushed him too hard and over the edge, "homeschooling" may well be a factor.
Perhaps you all would do well to remember that next time a 'publik skul' kid goes nuts.
It's very clear from his writings that his upbringing was in an isolated and horrible environmnet. The experience severely damaged him and left him incapable of working things out on his own.