That's like saying a book is not copyrightable because anybody who understands that language can easily copy it. Of course things built on the web in HTML5 can be copyrighted, regardless of how easy one can copy them.
Protecting them is another matter and I agree with you on that. You can go to great lengths to obfuscate the code or whatever but in the end anybody with enough skill and motivation will be able to copy your work.
People can write ripoff books that are different enough to be free from recourse. In HTML5, the platform is even more narrow than natural language. A "thief" has available to them all of the approaches, quirks and libraries of the original author -- none of which is exclusive.
Together with the lack of practical enforcement, there doesn't appear to be any utility in the law. Saying an HTML5 web app should be protected by copyright is a bad joke at this point.
It's not a bad joke, and what he is selling is not a web app either. There is a lot of open source projects that you have to buy commercial licence in other more closed languages.
What he is selling is a programming framework to do games and it is not licenced to be resold, simple as that.
If the guy would be in the US, it's clear that action would be easily enforceable. Softlayer should atleast take down the website.
Protecting them is another matter and I agree with you on that. You can go to great lengths to obfuscate the code or whatever but in the end anybody with enough skill and motivation will be able to copy your work.