There is nothing in the page's content or about its place of publication that suggests it to be potentially legitimate. I could have easily come up with a page published on Azure that had been unpublished to have this situation. This could be a hoax. I wouldn't trust anything about it until properly acknowledge or published by Microsoft.
I don't think that's interpreted as go faster that the speed limit if others are. I believe it's moreso not to drive aggressively. If the person in front of you is driving 40mph, you shouldn't be going 45mph even if the speed limit is 45mph or higher. I'm not a Californian though so it's possible your interpretation is correct for that jurisdiction. Thanks for citing what you were interpreting as allowing one to drive faster than the speed limit though.
Please cite this. I looked at the online California Driver Manual and I find to the contrary that most things say slow down in congestion and other situation. At no point does it say go faster than the posted speed which is a maximum for normal conditions.