I mean. They're human. This was a tweet, not a news article. People are allowed to be upset and say stupid stuff. We all do it. We shouldn't lose our jobs over it.
If someone's job was to say "guard a vault" and the vault is robbed because they had a bad day, it's reasonable they are fired.
I don't think this person should be "cancelled", but I can't imagine keeping this person in such a role.
In general, the outrage and retribution mob too often defenestrate proportionality.
It could be a good idea for such accounts to be held by a social media commenting approval dept acting as an extra layer of humans to double-check, e.g., "do you really want to post this as-is?"
They made the rules. Now they get to live with them.