It is not about Bitcoin. It is desperation. It is simply about stealing what others have. He is not a fan of Bitcoin that is why he did that. He is simply a criminal.
If you want Bitcoin, work for it. Make a place for savings in your regular salary and use it to buy Bitcoin. Accumulate slowly through DCA. Little but little, you can grow your Bitcoin portfolio.
You can reduce your unnecessary spending also like smoke, alcohol, and other vices or costly leisure activities like travels, parties, etc. You can use them to stack Bitcoin instead.
I agree, such a nutcase would also do it if it wasn't regarding a Bitcoin wallet. Such people don't want to work for anything, they just desire what others have and are hateful towards someone else's success. Torturing someone and demanding their money is something only a mentally challenged criminal would do. Okay, if we suppose that he got the money then what? Did he really have the belief that he wouldn't get caught? You need to be extremely naive to think that such a horrid crime would go unpunished.
maybe he thought that once he got the money he has enough to just disappear and not get caught after all when you have huge amount of money pretty much anything can be done this is why a lot of criminals who were to able to steal a lot of money can disappear and hide somewhere for quite some time
it also just possible that he did not think this through and he acted impulsively and irrationally.