Asking someone to "hop on a call" is phrasing you use with someone you are close with, not someone whose work you've just destroyed and is no longer interested in a relationship with you.

The fact that the preceding apology was absolutely awful does not help. "I'm sorry for how you feel" is wrong, since nobody asked them to react to "feelings" but the clearly delineated problems with the automation that Mozilla rolled out.

Asking to discuss something like this over synchronous voice comms is basically asking to go off the record and handle things privately. Sometimes that's appropriate, but if that's what the correspondant wanted they would have asked for it.

These three things combine to tell anyone who is paying attention that this is damage control, not meaningful engagement, and it's offensive to act this way toward someone who has put this much time into your project.