You're completely ignoring the "preferences" part of that statement though. It's unfortunate that he threw the "abilities" bit in there as well, but when reading in the context of the rest of the memo, I think it's fair to say he Damore believes the distributions differ due to "preference factors", much more than he believes its due to "ability factors".

And a very strong case can be made that women make different life choices which result in generally different outcomes in those areas.