Better not let the kids in the workshop. They could think the tools lying around there are made by professionals so they'd be safe, resulting in them getting hurt. And the metal and wooden dust from the saw someone used there could get into the wound and that could get nasty. Really, better just tell children to never go into workshops, or tinker around at all, for that matter.
Your comment serves as a poster child for what I'm talking about. Arrogant, looking down on others, deriding their efforts.
Crypto is really, really easy to screw up. If you screw it up in production software, the consequences can be anything from "fifteen million people get their credit cards stolen" to "a teenager in Saudi Arabia gets beheaded for treason".
People have every right to learn about and experiment with crypto, but it's just too important to treat as a plaything. If you're marketing your software as "cryptographically secure", you're asking users to place their trust in you to keep their secrets safe. That's a tremendous responsibility and we should treat it with the utmost seriousness. People who should know better keep shipping software with utterly broken DIY crypto, so we need to keep hammering home the message that you should never, ever roll your own crypto in production software.
If someone asked questions on StackOverflow about how to perform brain surgery with kitchen implements, we might want to indulge their curiosity, but we have a moral obligation to say definitely don't do this, because performing brain surgery in your kitchen is an outstandingly terrible idea and someone will probably die. Right now, the software industry is suffering from an epidemic of kitchen brain surgery and it urgently needs to stop.
You're reading some weird things into what I wrote. There are some real concerns with implementing your own crypto and getting it wrong, but the people listening to "Don't roll your own crypto" should be ignoring it, and the people who shouldn't be rolling their own crypto already are ignoring it, so it's useless advice. If you want to roll your own crypto, be conscientious about it, that's all.
And I have no need to deride the people who shouldn't be writing crypto. The exploits are factual and speak for themselves.
Having respect of certain things is healthy, and learning things under (expert) supervision is generally effective and safe. Think about cars or electricity. Most societies have some kind of mandatory training for both.
Do most hackers have the patience for learning the basics, i.e. some somewhat complicated maths that could take years to learn? No, most of the time it's programmers, and we tend to just start writing code. That's what "don't roll your own crypto" means. Nobody's saying "don't learn about Galois field" or "don't run through cryptopals".
The Dunning-Kruger effect is real. I've seen broken crypto getting shipped. Or people releasing dangerous crypto under "hey, I made this perfectly functional library that even has documentation how to use it, but it's just a learning project". So while that's still happening, I'm fine with hearing "don't roll your own crypto" ad nauseum.
Your comment serves as a poster child for what I'm talking about. Arrogant, looking down on others, deriding their efforts.