What was tried was an appeal of the reviewer's conclusion,

Yes. This is what I am describing as you arguing with the browser vendor for two weeks and then missing your deadline.

I get that you're trying to reframe it as a discussion between equals, and acting like I'm somehow being unfaithful by declining.

This was not a request, a discussion, or a negotiation. The repeated attempts to treat an ultimatum as something open to discussion got the plugin, and probably the developer, perma-yanked.

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which seems like a perfectly reasonable procedure

It's not clear to me why you are insisting that your attempt to convert "you have X days to accomplish Y or you're done" to a negotiation is somehow reasonable.

It isn't.

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I don't see why Mozilla should get to say what setting a user can set in their own browser installation.

And that's why you're no longer allowed to write this.

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You are well aware that Mozilla has to sign add-on, which it might refuse to do

I fully expect that, actually.

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They can also simply blacklist the add-on, against users' wishes.

I fully expect that, as well.

That's the correct next step, when a vendor tries to fight against basic security, and pretends they have the expertise to debate, even though you're trying to frame this as a user freedom issue.