It's common practice, you know. Maybe someone did tell him that, and he turned out to be more of a grumpy old man than anyone expected, and sued them. In the office culture the oldest employee has a position that's not necessarily very respectable, although in some countries age does matter more (like the more traditional Japan).
It's safe to say, however, that the person's age is not important - the attitude is. If you've got a clear head and friendly attitude at sixty, you can be the most important person in the group (in the office, too). That article has nothing in the man's defence.
Then God said, "Let there be win",
and there was win, and it was good.