That is true, but remember, all of that happened in 1939-40. After that, Batman *totally* never killed (according to the writers and editors). This was not just about "thinking of the children" (though it was certainly a factor), but also to make Batman look less like The Shadow.
It was mostly about not getting the magazines pulled from newsstands due to violent content, which wound up happening in the 50's. Read 'Men of Tomorrow'. It's a very good look into the goings on of the American comic book industry of the time.