Whenever something like this happens, people like to dismiss the situation by saying we can't possibly understand "crazy" people. It avoids having to consider the systemic reasons why something like this can happen.
I'd imagine a significant part of it is that we live a society where some people can have their livelihood yanked away from them, with no support structure to help them, leaving them desperate and angry.
I'd imagine a significant part of it is that we live a society where some people can have their livelihood yanked away from them, with no support structure to help them, leaving them desperate and angry.