Do we really need more public shaming without at least a civil discussion between the belligerents? Remember Adria Richards anyone?
For example, I've used toooons of open-source code in my life, lots of snippets, and I've not attributed every single thing although I usually do. When I copy a pretty standard implementation of a sorting algorithm that is used in a minor way to present the final results of some fancy code I completely wrote myself, sure, contact me and ask me to attribute properly and I will. My intention is to build something new, and use some code here and there by others instead of reinventing the wheel, and sometimes you slip up and don't track your attributions properly.
But in this case, nothing new seems to have been created, it seems to have been almost entirely copied, variable names changed specifically for no real reason (it's one page of code, on a big project I understand changing variables to suit your project structure but on a one-pager...), and the work is even referenced as being inferior (by pointing to a 2 year old version, saying that is inferior, then copying the 1 month old version that already solved the issues you're pointing out on the 2 year old work, and not attributing anything). At that point, the notion someone is a cool dude looking to build cool stuff and made an honest mistake goes out the window, and the chances you're dealing with a guy who inflates his own ego while dissing an author he's copying and goes out of his way to muddy the evidence he's copying, pretty high. In this particular case I can really see where OP is coming from in not resolving this by email.