Seems to me Rule #5 is your standard CYA.
Which, I have no problem with.
In general, it is a quite common forum rule, i.e.; "this is our forum and we reserve the right to let you stay or send you packing. More over, should we decide to send you packing, we reserve the right to keep the reasons we did so entirely to ourselves."
Don't get me wrong, I mean no disrespect. In fact, I use the same rule in my own forum, and it is pretty much stated there as I have stated it here.
Whenever interacting with a group of people, strangers or friends, and discussing topics which folks potentially have very strong opinions about, and topics which can, at times, spark quite passionate if not volatile debate; I find it best to follow two simple rules of my own:
Rule #1. The Golden Rule
Rule #2. Stick to the topic