So I'll pose the same question I've posed before. Why is it that we admire "low hangers" on fit and/or young guys, but those same low hangers are condemned in statements like "Some old guy in the locker room with a low-hanging scrotum"? Seems like a double standard.
I'll take a shot, I think these are the stereotypes you are seeing;
On a fit body the low hang suggests virile testis that need to move far from the body to cool off as they are working so hard (wrongly suggesting they are going to send the motherload of cum).
On an old wrinkled man they are just more loose & wrinkled. In their context they just seem spent, and we tend to think of old men as slow but kindly grandpa & 'everyone knows' old people are non-sexual.
Double standard based on not knowing the stereotypes are easily & often wrong.
That would be my guess.