Well, I consider myself knowledgeable enough to easily survive similar attacks, even in the worst case scenario where instead of few thousand files I had to restore everything, ground up.
But to many, being hit by ransomware means a big deal - economically, emotionally, psychologically.
Generally speaking, choosing to harm others in this way has no justification, if not in a very broad sense.
I don't hate this person. But I don't particularly like him/her either that much.

Of course, we cannot know. The guy may have had a gun at his head, or what not, for what we know.