It seems to me he was expressing a reasonable opinion that, if adopted by all, would lead to less whining and QQing. Even if it isn't enforced by GF, doing the right thing and making the choice you want others to make if they were in your shoes is beneficial to everyone. As a mage, I have often been tempted to hit that forge or processing factory within t-storm range of a gate, but would I want to come back to my castle with all 3 gates up and find missing buildings? Stop asking "What can I get away with?" and enjoy a good battle, hard-fought and honorable. Besides, he said "Take it as guidelines or as a point of discussion, I don't claim to make actual rules out of it because that is beyond me, but so far doing it like that worked good, and without pointless drama or cheating accusations. " I look forward to any siege where I know the opponent fights fair, even if I know we're gonna get slaughtered because the fun is in the battle, not winning at any cost.
Edit: Apparently I took too long to type that and someone already responded, sorry.