Or is it "To make an apple pie, you must first invent the universe" kind of deal. Which doesn't make sense to me either.
In the same way a program manager is free to say "We build X from scratch" even though they made no code contribution to it. The we is replaced with I since no other person was involved in this case.
That's fine for bread, but for people that see code more like art, they have a preconceived notion that "from scratch" means writing the code yourself.
Some people code to solve a problem and they don't care how it gets done. They have no problems using AI and see other methods as prehistoric. That's fine for them, carry on.
For me, the journey is more important than the destination.
Being able to code "by hand" is what strokes my sense of worth and accomplishment... knowing I can do something that not just anyone can. Pushing a button or prompting an AI isn't the same for me, that's more like a project manager and something I never want to be.
When people bash on the anti-AI crowd, they just don't understand that people code for different reasons, and neither is more right or wrong.
Code can be art, making food can also be art. So I'm don't agree with your distinction that code is materially different from baking in that aspect.
The terminology "from scratch" and "by hand" are really not interchangeable in my opinion. "By hand" implies something about the process. "From scratch" implies something about the state before you started, not anything about the process.