It’s because we think a twenty year old deriving their sense of value from how much sexual attention they can get is going through the almost inevitable, or at least common, growing stages of youth. A 65 year old doing the same plainly didn’t succeed at growing out of that.

If you don’t think there’s any sense in which it’s good to grow beyond 20, that’s your call and you’re allowed to make it. Most people who go through adulthood find the way they relate to the world evolves, in a positive sense, over time. Some wisdom is achieved. And people who clearly never went beyond who they were at 20 failed to obtain that development.

Same way we don’t judge 15 year olds too harshly for stirring up high school drama for attention - it’s par for the course in growing up - but we would judge a 35 year old man who spreads rumours and causes drama for attention. Because we expect people to mature a bit.