So I'm a complete outsider, but they do not appear to be in the same position as the poster. They are marked as "Mozilla Staff" and "SUMO Administrator" (amongst many other things), neither of which the complainant is marked as.

It is true both they and the person they are responding to are marked as "SUMO Locale Leaders"... but it seems rather clear from the context that is not the role they are inhabiting in their (non) apology and request for a "quick call" with the complainant.

The language they use is certainly not the language a peer would be expected to use either.