That’s curiosity and science, too.
Fortunately, he lost interest after having successfully bred the mold, and never carried the attack out. But you know what, I don’t want kids and sociopaths having easy access to biotech at home. Who knows what hacks will ensue that could devastate crops or economies. The OP says that is a small likelihood. The truth is he has no model that allows rational computation of the risk. The truth is he has faith.
The author of the post understands the practice of science but not the sociology of trust that goes with the community of scientists. I don’t care how safe he declares his ideas to be, it’s not in societies interest to have “Joe’s homemade injectable health serum. You can trust ol’ NASA Joe” available at every roadside stand.