How is politics defined with LW?

It isn't. But by any definition respecting ordinary language, creating a fooming AI is a very political act. Yet the subject has been discussed many times on LW without anyone's mind being killed. (Some minor injuries, perhaps ;) ) Thank goodness the LW community doesn't take its own rules too seriously.

There is no need to start a thread on the public and private sectors' roles in health care. But if the subject comes up naturally in a discussion on, say, seeking psychological expert help in overcoming some form of irrationality - then let it. Let it be touched on (not displace the original topic) as far as is relevant. Putting up crude firewalls is not worth the price in artificially constrained discussion. The "slippery slope" isn't - as demonstrated in the response to Mass_Driver's recent thread.