GP is arguing about licences. Yes, formally there is no obligation, and I'm not saying the author has any such obligation.

In the present case, either the missing overflow check in the code is by mistake, and then it's warranted to point out the error, or, as I understood GGGP to be arguing, the author deliberately decided to neglect safety or correctness, and then in my opinion you can't reject the criticism as unwarranted if the project's presentation isn't explicit about that.

I'm not making anything the author's problem here. Rather, I'm defending my criticism of the code, and am giving arguments as to why it is generally good form to make it explicit if a project doesn't care about the code being safe and correct.