You get a better return from people who want to work for you than from people who are "not that interested". If I was hiring and a candidate first submits shitty code, and then says he's not that interested, then I'm quite likely to lose interest too. It has to be a match on both sides.

Candidates shouldn't be groveling on their knees, and any hiring manager who expects that should be avoided at all cost, because they're selecting on willingness to be abused. But it shouldn't be the other way around either; hiring an asshole is not good for the company.