The problem is that it's easy to do it wrong and the C compiler doesn't help you. RAII prevents you from leaking the resource, but the complaint in the post is

The problem is that it's easy to do it wrong and the C compiler doesn't help you. RAII prevents you from leaking the resource, but the complaint in the post is that it can be cumbersome to use RAII in C++ if acquisition can fail and you want to handle that failure.