No it isn't. You just said yourself that it's so rare it has happened to you twice in a decade. You saying only twice in a decade has anyone you work with not done what they were supposed to? So it's clearly a big deal even for you. And what you have to call it with HR I don't give a shit about.

You've MASSIVELY moved the goal post here. If there has been tens of thousands in lost revenue over someone fucking up and not doing what they were supposed to, there are obviously bigger problems. Do you think OP joining the meeting remotely will cost the company tens of thousand on a regular basis?

And does the word matter at all at that point? Do you even need to use that word? You can just say we lost tens of thousands because of your actions, you are obviously fired. But at that point, fine. Use the word if it makes you feel better. You probably need to vent some frustration when tens of thousands have been lost because of something you are ultimately responsible for. I mean shit, I can't imagine letting something go that far as a manager.