If you get beat up walking down the street, is that your responsibility? Sure, in the sense that any idiot can always find ways that you could have avoided it if only you had done something differently. And in the very obvious sense that nobody else can suffer through the pain of a broken nose for you.
Seriously, it's not common sense to assume that an employer will behave stupidly once you announce your intention to leave? You should assume that you'll get walked out when you hand in your resignation, and that after that, your former employer will not play nice.
In small companies, I've seen owners contemplate/prepare nuisance lawsuits just to make examples out of recently exited people for sheer pettiness. And these were employers who would have been perceived as stand-up guys before the people quit.
It's a pretty old rule of thumb that you get your ducks in a row before quitting, just like you shouldn't accept any counteroffers from your employer after you hand in your resignation.
The OP gets some sympathy from me for getting shafted, but he gets no sympathy for being naive about how to leave a company.
Isn't it common sense to assume that there are dangerous people in the world? People getting assaulted should have known and taken appropriate precautions. I don't have any sympathy for them. Don't they read the papers?
You're not getting it. With hindsight, you can always find a way to blame a victim. It's great fun: you get the chance to look knowing and smug, and your success rate in predicting the past is 100%.
Don't kick people when they're down. You end up looking like a heartless jerk.
He's not a victim of a random crime (per your analogy, which to me is not apt), he's a victim of his own naivete and inexperience.
In the same way you had better know to take all of your most expensive gadgets out of your soon-to-be ex-girlfriend's apartment before you break up with her (lest they get smashed with a hammer), he should have done the same.
This is not even close to rocket science. To assume that people will behave like adults when you sever a relationship with them is extremely naive.
