Because I was told frequently by others something completely contradictory. It would be extremely useful to me to be able to say: "No, your position not only is not the only reasonable one, there are other positions which specifically assert that yours is and has always been the unreasonable one."
Hence why I have been asking if that's really what this person actually means to say, or they actually mean something rather weaker (e.g. "we now understand that this is what 'compatibility' meant, even if we could not have known before release'.") I want to be sure that I am fully, properly understanding them so that I can point to this later with unequivocal verification--so that no one can say I somehow misunderstood, or somehow took someone's position too far, or that I invented a strawman, or any other such argument dismissal without engaging with the substance of a point.
And, to be clear, this is far from the first time I have said such. Not on this specific topic, mind. But I always do so with the specific intent that, if the person instead says, "no, I didn't mean something that strong", they are fully within their rights to do so, and I won't hold that against them. It would be extremely discourteous to say, effectively, "are you sure?" and then skewer them for choosing to be more cautious about the breadth of any given claim. But, if they are sure, and say as such, then that may significantly simplify future discussions with other people.