Stalking is defined as two unwanted contacts. So, no, it's not loosely defined. If you notify someone their contact is unwanted, and they continue to approach you and try to have contact with you, then they are a stalker.

And I'm not discounting that someone who is a stalker may not be aware of their behavior. I know the thread that Eskie is referring to, and, yes, these people are suffering from their own illness and demons. I don't like generalizing them as psychopaths or any other derogatory term.

But legally the behavior is called stalking and they are stalkers. Having an illness does not make them any less of a stalker. Having a mental illness is not an excuse for illegal or harmful behavior towards another.