Why do elders believe they can tell a younger person what's proper?

OK, I am an old man compared to you. Sons in their 30's. I find nothing wrong in how a young person has their hair. Long,short, spiked, blue, pink--- I think it is cool. The old man you met at the gym was out of line, and definitely lacking of common sense and manners. Oh and about older people being an insult to modern metal/rock music. If it wasn't for older people it wouldn't exist.