If people shouldn't be their own gardener, why should they be their own bank?
Do you realize this is a poor blanket statement?
Discussion
Holding your keys, running a node, ... These are things you do to not get rugged on your most liquid form of capital. It's private property protection. Just like you protect your house or industrial machinery from theft, you do it because it's literally worth it.
Growing food, on the other hand, is production and is something you can choose to do for pleasure, profit or because you want something the market doesn't provide. On a bitcoin standard all three of these reasons lead to you specializing, scaling up or quiting.
Yes. You are right and I agree with your main point. I just wanted to point out there is in fact nuance.