He writes "prepare to cringe" and he is not wrong. As far as I understand, this technique implements GOTO by reading the source code (again) into memory, filtering out everything before the target label and evaluating the remaining source code. I think this doesn't preserve state, variables etc. so not really a GOTO. But interesting technique.
The more frightening part (at least for me) is the reddit thread that points out this is how windows batch files implement goto, and shows how to see it happen.
edited for clarity