You've articulated my anger and exasperation perfectly.
There's a specific brand of ageism especially directed at Gen Y -- although Gen X and Gen Z aren't immune from it, either (due to all three generations being younger than Boomers).
It's entitlement. It's self-loathing. It's pitting groups against one another to maintain power. It's a dash of cultism.
Yet, its offenders still stubbornly REFUSE to acknowledge how there can be a lot of anti-youth ageism...and they continue to insist that older people are "primarily" the targets of ageism.