Lemme tell you now, so you don't get blindsided: your attitude thus far is going to make potential helpers way less likely to assist you, even though your questions might be legitimate. We are spending our time here as volunteers, not getting paid anything, and we like it if askers meet us halfway and try to be less hostile. Now, wouldn't that be nice? – Guess who it is.♦
As an established member of our community, valued long-time contributor, and former moderator pro tempore, Sjoerd is well within his right to write in an authoritative tone when addressing a new user regarding site guidelines, from his memory or otherwise. "Guess who it is" (J.M.) is an active, community-elected moderator (as am I) and is further entitled to speak authoritatively. If we privately arrived at a site policy it is no less valid that one established by public Meta Q&A consensus. I am genuinely sorry if this rubs you the wrong way but I feel we are well within the will of the people in what we do.
My memory is not as complete as I wish so I cannot directly support J.M.'s statement that "this was community consensus" but my point is that it really doesn't matter.
I am not saying that site policy is written is stone. That's a major part of what this Meta site is about: developing and improving policy, which is why I thanked you for your question about WPC. Questioning site policy, wording, etc. can be helpful and I have attempted to be responsive to you regarding it. However as noted repeatedly by others your attitude comes off as abrasive; if you want your inquires to be received and respected you need to work to improve that.