It's profoundly unreasonable to pass off unbacked assertions as any form of reason
I've provided sound reasoning already, refute it.
I would if I could find it, but from what I see you've taken some facts, made up a story around them, and then because your story fits the facts you say it must be true. But of course your story fits the fact, you used them to make it up.
I am being pragmatic
Bitmain could pre-emptively fork themselves during an unknown 24 hour timeframe, with 75% of the hashrate and a pathological desire to destroy Bitcoin, why do they need to even pretend to be cautious?
Its very unreasonable to assume that have a pathological desire to destroy Bitcoin.
Is it unreasonable to assume they have a very pragmatic incentive to destroy bitcoin, like state-funding and influence?
No, but its unreasonable to assume that because they have an incentive they must be doing it. You seem to have seen a possibility and jumped from it being possible (but quite unlikely) to saying it must be true.
We all have incentives to rob, murder and rape people all the time. We generally don't do it though, and to assume that people are doing that is not a good thing.