If you remember a few weeks ago, Classic had around 70% of hashing power, but apparently, that was "not the issue" and was not "indicative of emerging consensus" etc. etc.

I have a feeling that letter is a fraud ( or at least grossly misrepresents certain views) based on at least 2 of the signatories. Its the kind of thing you would expect when Classic has almost 1/3 the nodes of Core 11.2.  I imagine a whole lot of frantic canvassing/pleading has been going on in the background, and people like to keep people happy when they call to the door.  The real vote will be adoption. It either gets 75% or it does not.