1. Select the right audience for your message. (E.g., Does it need to go to the Google founders, or is the true audience open public since the problem is still bigger?)
2. Educate your audience ahead of time, or at least as the opening part of the message:
2a. What the intentions for the message are? (E.g., help understand the true root causes of diversity gaps, reiterate that there are invalid opinions commonly held, and also boldly indicate that someone needs to stand up even in a culture there people do not openly share such analysis and/or opinions.)
2b. What the approach is (which would be to deep dive into the correct root cause of the issues (e.g., why working women have lower average salary than working men)? And explain that without understanding of the true root causes, it will only take longer to reach the optimal balance, never reach it perfectly, and the current situation may already be the maxima under the current set of beliefs.
2c. What are common pitfalls and misconceptions (e.g., assuming all gender gaps are coming from discrimination as the memo writer noted)?
3. The core message:
3a. What are the knowns (existing research) that points to the root cause?
3b. What are the unknowns that still need researching?
3c. Summarize the proposed next steps.
4. If as a result of capturing all of the above, the message is becoming too long:
4a. Revisit if you are targeting the right audience.
4b. Split it into smaller logical blocks, and deliver them in steps, so that people can actually follow, getting convinced along the way, rather than get inflamed.
5. There will still be people unfortunately who would not understand all this but who will resist nevertheless. A second round of explanations/FAQs would be needed to address them.
6. There will still be people unfortunately ... (Your approach above should be devised to help reach consensus.)
7. If at any point you realize that something was wrong in your own thinking, correct it, and revisit if your broader message still stands and is worthy. If you come out wrong too often, it's good for you (having learned something new), but be prepared to loose trust.