They only meant to say that Bethesda did optimize throughout the development process. You can’t do gamedev without continually optimizing.
That does not mean, Bethesda pushed those optimizations particularly far. And you can definitely say that Bethesda should have done more.

Point is, if you ask “Why didn’t you optimize?”, Todd Howard will give you a shit-eating-grin response that they did, and technically he is right with that.