Where do you work now? And also, I've heard that at Google for example, there is prejudice against older programmers? Have you experienced anything like that?
It really boils down to what I've already said. A company is its staff. What its staff does and accepts other staff doing is ultimately its policy. Anything else that they might have written down into a document that isn't enforced or followed is not company policy, but a way to compartmentalize responsibility and blame once its actual policies come under scrutiny
The company (and the law) have rules about discrimination and fairness, but when a group of 20-somethings interviews an older programmer those rules may not matter. Fixing age discrimination probably shouldn't focus on laws and company policies, no company has a policy condoning age discrimination that we need to fix. It's the software dev culture that equates age and experience with "not a good fit," for whatever reason. I have my own theories what those reasons amount to but regardless of why I think it happens, it clearly does.