This is not true. The code can be flawless, slightly buggy, maintennable with some effort, hardly maintennable or unfixable. And then there are personal preferences and opinions about what is good code.
The algorithm can be slow, slightly faster, fast.
The intro into framework can be in the middle too.
But within context of a tutorial, anything less than flawless is not worthy of inclusion (making it binary in this case). IMO, any content aimed for beginners should be flawless.
Beyond introductory material, it's a trade off of complexity and time as it's hard to compress the factors needed to demonstrate anything technical.
Pretty much all motor skills like like Karate can be performed okay, good, better, really good, etc. Similarly, I can take gradual baby steps from being a bad photographer towards becoming okay and then good.
But for most programming things, it either works correctly, or it doesn't. There's very little middle ground in an algorithm. Either it works to solve your problem, or it doesn't. Accordingly, I don't believe I can learn much from someone else's broken example in the way that I could learn from a (mediocre but slightly better than me) photographer.