Following your point of view, code-academy's approach is equally shitty. The airbnb "website" is not just a front-end with some HTMl/CSS and 4 png images that you've put together and will give you an airbnb clone.

There's a heavy backend, multiple servers to setup, manage and monitor. Then there are databases, SSLs configurations, privacy concerns, http requests that need to be routed, emails that need quick replies, fault-tolerance strategies, CDNs, authentication schemes, payment gateways, rating systems, backup schemes...

Did Code Academy teach how to handle all of the above or are you referring to a front page that I could fetch and regenerate in 20 seconds using curl?

I think the purpose of this website is a little bit personal to the developer, he is just showing his friends (and now other people) that getting a site up and running with a domain is an easy task.

The site also doesn't say to copy paste the contents (read point 6 and 7) so your example is a bit strange. The site doesn't even mention to copy paste anything as far as I saw.