The MIT License – Clarity on Using Stack Overflow Code

This to me (and excuse my ignorance) seems like a waste of time and money (on real-life lawyers). Stack Overflow and the associated sites are public forums, the users posting code surely realise they're posting information into the public domain and as such it should be recognised as being in the public domain.

Nobody (at least as far as I can tell.) is posting proprietary or self-written code under the pretence that they will receive attribution under a nominated license. It's a question and answer website, it's not a repository for complete software or work that needs to be protected under license.