Big picture

> Marcan’s one of those people whose grievances all look individually reasonable,

Okay, so we have a non-trivial set of grievances each of which has merit in isolation. 1+1+1+1+1...

> but when you add them all up it suddenly [suggests an implausible, or at least deeply distressing, result].

equals -1.

This process resembles nothing as much as shooting the messenger, or fallaciously rejecting a valid deductive conclusion because you don't like it. That's the opposite of a reasoning process.

When diagnosing this sort of surprising result, you should work harder to understand what's going on. Maybe you're right to reject the conclusion you reach (even once deflated of the hot gas you pumped into it when writing). A couple of approaches come to mind.

1. You noted a suddenness to the process. Okay. Delete marcan's grievances individually, one by one, until you reach a different conclusion that follows from them and yet doesn't surprise you. What is that conclusion?

2. It is sometimes the case that a person makes some decision premised on grounds that they don't disclose, then retrospectively cobbles together a "case" for it that bears little resemblance to the reasoning process they actually used. This comes up frequently in employment law cases, where a finding of a tortious or unlawful firing of an employee is made because the employer offered "shifting rationales" for termination over time (with the biggest differences typically showing up once the matter gets litigated and the employer retains professional legal advice). If you think that is the case with marcan, then the burden is on you to establish that he had some other basis, one the community would be less likely to accept as legitimate, for his decision. (Like, say, "too many Linux kernel people casually inspect their own names and reach the conclusion they're without sin".) Such a claim will demand evidence. If that exists only locked up inside marcan's scheming mind, then you have no objective evidence to offer.

In sum, the onus is on you to explain why 1+1+1+1+1 doesn't equal 5 here.