It's interesting how we can use age (selectively) as a discriminator, but within a certain range and in certain contexts, it's seen as "bad" to discriminate.

Most wouldn't say the concept of a retirement age is discriminatory, nor the concept of age of consent or minimum age to purchase alcohol, or pricing insurance rates differently based on age.

Somehow this application of age discrimination seems to cross the line for many people, though. I'm genuinely curious as to why.