*shrug* It's just something I've observed, it could be entirely different in your country and cultural setting. But in mine young people are the most common gamers. They are predominantly male, too. I'm not being discriminatory because I'm not saying anything bad in light of those facts. Such as in Australia, the Indigenous Australians are over-represented in gaol. That's a fact. It only becomes discriminatory if I were to say that it's because they're inherently criminal. (Which I wouldn't say and it's not true).
You didn't say 'Warhammer player in my neighbourhood', you just said 'Warhammer players'; so I thought you meant all Warhammer players (but I forgive you ). If it's just Warhammer players in your neighbourhood, you are right: that's not discrimination. And by the way, all Warhammer players I know are young as well...