Your assumption is that a 11 second delta is a somewhat better evidence than a 90 seconds delta, but the provided article successfully defended this isn't the case IMO. It depends on the last activity of the user

The article also shows that there's a 40 second delta between the harassing account and the harassed person himself, further semonstrating this doesn't mean anything and can happen purely by chance

It does not. He said that if we're using approximately similar times to establish identity, then by using that logic, it could also establish that Schestowitz was that alleged sockpuppet account. (Transitively, does that mean Garrett and Schestowitz are the same person? Have we ever seen them in a room together? Hmm.)

But honestly, anyone who ever spent any amount of time on IRC is used to seeing 50 people drop from a channel at once. That was usually due to netsplits, which isn't the case here since there was only one IRC server involved, but that wasn't the only cause. "Uh-oh, the IRC server got too laggy and couldn't service all requests within the configured timeout. Time to disconnect everyone!"

For sure. Having lived on IRC for a while many years ago, I assure any bystanders that this is assuredly not always the case.

Ergo isn't a federated server, it's meant to scale vertically

After "being warned of the consequences on multiple occasions the Schestowitzes never provided any witness statements", so that's hardly Matthew's fault.