From where I'm at, your initial statement was more like "If it rains bricks, you need an iron umbrella," and my counterpoint was "True, but it never actually rains bricks, and an iron umbrella is not great to protect from rain because it's heavy and it rusts," To which you kept repeating, "Yes, but if it rains bricks, you need an iron umbrella."
I agree that yes, Lephys, indeed, if it ever rains bricks, then an iron umbrella comes in very handy, but I still contend that in reality it hardly ever rains bricks, and therefore carrying an iron umbrella is a bad idea.
I'd find that point to be immensely more potent if we weren't talking about an entire genre of games based on fictional worlds.
Translate your point back to the original example/debate, and instead of "Yes, but it never rains bricks," you get "Yes, but both swords AND maces are never both necessary, ever."
And you know what? As long as it never rains bricks, in reality, then we'll never have any use for iron umbrellas. That doesn't change the fact that, were bricks to ever be raining down upon your head, you would no longer deem an iron umbrella to be pointless. Thus, even if you never have to be in the situation to desire an iron umbrella, because it's never going to rain bricks, you can still comprehend the relationship between the value of an iron umbrella and the existence of brick-based precipitation.
Thus, the one thing you still don't seem to get is that the point of even that silly example has absolutely nothing to do with whether or not it ever rains bricks. If you understood that, there'd be no reason for a "but."