I'm not sure how scientific we really need to get about this. Go to San Francisco, go to Palo Alto, go to Mountain View and hang out with startup people. You will see this multiple times a day, and it will pervade your entire impression of the industry.
This phenomenon is not a secret, nor is it obscure.
Oh, I am not disagreeing at all that this is a fact.
Just that the numbers they used to support it are a little weak (LA likely has worse age discrimination for example). It would have been better to not state numbers at all and stick to the rest of the details in the story.
This phenomenon is not a secret, nor is it obscure.