Sorry, I wasn't the most clear. I called it insane, but I don't think you should actually think the example is insane, by your logic. You said you don't think someone should need to justify why they don't want their mod ported.
If you don't think it's insane for people to tell someone which version of SRB2 they can play the mod in, why do you think it's insane for people to tell someone which levelpacks they can play it in?
I know the answer most would give is because "it requires editing the mod to make it work in another version" but I actually want to know if you have anything more than that. We don't allow editing another person's art because we value the author's vision for the mod they made. In this case, it's literally an issue of copyright, as well.
But in terms of a port, do you think it's fair for the author's vision to extend as far as "you are only allowed to use my mod on this particular version of the game?" And how is that any different than if the author's vision were to be "you are only allowed to use it in this particular level pack"?