Dogfooding has a big history in Sillicon Valley and kinds of software development culture way before blogging was a thing. Before the web was a thing too. It was a thing people explicitly referred to before it even had that name.
Take your brickbats. I don't run one now, but I used to.
All of this is irrelevant (and ad hominem) by the way.
The situation is simple: Apple doesn't make a mouse good enough for its CEO. It's as embarassing as if a Dell CEO used a Macbook.
Whether that's still fine business-wise ("we still sell millions of our own mice to less discerning folks") is irrelevant. We're criticizing their mouse quality and commitment to making a good product, not their money making abilities.
It's not really that embarrassing. My dad's a surgeon: fits femoral nails. I've had fractures. Didn't put a femoral nail in me. Just wasn't a fracture that needed a nail. Not embarrassing that guy who spends every day putting in femoral nails decided not to put a femoral nail in when it came to his son.
I think you're being silly about this because you've committed to this bit. If you make something for someone else, doesn't mean you need that thing. You might even need a different thing. I don't get why this is such a big deal.
But, well, I was wrong about you running a company. Maybe I'm wrong about this. I'll drop it. I have a feeling you'll look back many years later and wonder why you thought this. But maybe not.
Apple makes and sells mice as part of their business, my dude. Any t-shirts they make is just a secondary thing for the merchandise store.
Making their software and hardware good enough for them to use and "eating their own dog food" ( https://en.wikipedia.org/wiki/Eating_your_own_dog_food ) is important.