You're not being misinformed, this is probably good advice.
Your demographic information doesn't have to be on your CV for your name to be cross referenced with a government database (audits I mentioned are done by government offices or government contractors), which you would probably be listed in if you are working in the US.
>Isn't Google ratios similar to Facebook and other companies in San Francisco? (But not to other states).
I haven't read anything about any audits that have said they have a significant bias one way or another, I don't think I've said anything to suggest otherwise.
Google and other large corporations are known to do self audits of their hiring practices (demographic and otherwise) both to improve their hiring processes as well as to identify and correct discriminatory practices (mitigate legal risk), they are allowed to collect demographic information for the latter purpose.[0]
[0]https://www.shrm.org/resourcesandtools/tools-and-samples/hr-...
My personal opinion is that Google's demographics changes are a simple result of changes in the actual applicant pool, and that Google 'promoting diversity' doesn't change their internal hiring process in any meaningful way. But the press about it probably does encourage lesser represented people to join CS majors in university. So google does promote diversity in engineering, just not in the way the author of that article suggests, and instead with marketing and a 4 year time lag.