Please note the shifting goal posts. At the start of this comment thread you were saying that Damore's memo was certainly unscientific, and now you are arguing that there needs to be a higher bar for action than the fair assumptions that Damore made.

Keep in mind that Damore is a single person giving feedback to a diversity course. He doesn't have the resources, time, or mandate to survey Google's employees to test whether or not this general trend holds. Perhaps, before acting on Damore's recommendations it would be a good idea to do some tests on Google's employees to see if general trends hold true in their specific subset - but that is a really different claim than the initial claim that Damore was unscientific.

If Damore had written that smoking causes lung problems and therefore Google should start taking some actions to stop employees from smoking, it might be merited to do further tests to see if the link between smoking and lung problems holds true for Google employees as it does for people in general. It would not be merited to call Damore unscientific because he had not yet done that research prior to making his suggestion.