[random42_]

I don't think they ever said they knew they were the only one to know the admin passwords. Looks like they've heard it from former colleagues after they left:

> I heard from former colleagues that no one knew the admin passwords for their critical systems except me

And looks like they tried to address the fact that the entire sysadmin operation depended on them and management did nothing?

That's a lot of hostility and assumptions about some person on the internet and by the looks of it I'll make the assumption you've never worked on chaotic places where management is just shitty? I'm in the same situation at my company where I'm the only person managing our legacy CI/CD pipelines which are quite complex and nobody wants to learn it and management keeps saying they'll hire somebody as backup but they never do so I can relate to parent.