>it is still not age discrimination.
The law may not agree with you. Ever heard of disparate impact? "In United States anti-discrimination law, the theory of disparate impact holds that practices in employment, housing, or other areas may be considered discriminatory and illegal if they have a disproportionate "adverse impact" on persons in a protected class"
People over 40 are a protected class in US employment law.
Now, policies that can adversely affect a protected class are ok as long as there is a legitimate job requirement. For example, being able to lift 50 pounds may be a job requirement that adversely impacts women and the disabled but its ok as long as the job actually requires heavy lifting on a very regular basis.
Otherwise people are free to implement policies that are code for discrimination such as "able to lift 50 pounds" for a desk job.
You'd have to prove in court a legitimate job requirement. I think proving" likes ping pong and beers after work" being a businesses concern may be an uphill battle even if you call it "attitude."
Once you realize your hiring practices may exclude a protected class you really gotta do a second look over and ask yourself if it is really a business requirement. Other shops are able to ship products with more diversity and less ping pong.