I wrote an IP stack, of sorts, and used Wikipedia to do it. I'm aware that it's probably crappy, but only because it was basically designed to be. If I had tried to design it well, I might lead myself to believe I had done it correctly, for example because I found no problems with it in my testing. But as you're aware, there's plenty of problems with tcp/ip stacks that only come up as edge cases. So even if I was being sensible I might end up with shitty code and push it into a product, and then we're screwed. But if I had learned the stack correctly I couldn't be in that mess.

A kind of solution lies in forums like HN, though. Sure, the posts are fallible and are often upvoted merely because they are perceived as authoritative. But we have the comments section, and knowledgeable persons who can speak up and educate. So it may not matter at all who's teaching, as long as somebody picks up the slack.