Can't speak for that poster, but while I've used other people's code for educational purposes I am not aware of a time when I've used someone else's code against its restrictions. And bear in mind that code without a license notice is not a free-for-all, it's restricted until other rights are explicitly granted.

(I have no opinion on this situation nor am I qualified to judge it. Other people have a more fully-formed opinion than I do, and it does sound like it's properly open-sourced anyway.)