> They've been criticizing my generation for receiving the "participation trophies" they gave us as kids

Are you sure that the people doing the criticizing are the same people giving out the trophies?

> so I definitely mean it in a derogatory way against people their age

The way you had used it, as commentary on middle managers, seem to include people from Baby Boomers all the way to Millennials.

> I'm criticizing them as a cohort, not because of their current age

In which case it sounds like using the age identifier would be incorrect.