I believe what he meant was the leaked ISO was the full game, so there was never really a need for anyone else to dump it afterwards. With that in mind, " the leaked ISO was the ISO to get for USB loaders for a few years as well" making it "the definitive edition" for pirates.
So, if this one is leaked, and is the full game, it will not need to be dumped again, making it the ISO that will be around from here on out.
Therefore, your comment about loaders working long before was pretty much irrelevant. I assume he didn't care to spend his time explaining this, as well as derail the thread.