My grandpa doesn’t like my new hair style. All he said was “Meh”. He doesn’t like it! 😭😭😭😭

I’m 20 and my grandpa told me it was stupid of me to get purple highlights and what will my job think. He thinks it’s a shame that young women like me will do ridiculous things to our hair and fashion. He said Meh when I asked him what he thought.
My grandma thought it was up absurd for me to do that, but if it makes me happy, that’s all that matters.
I complained to my older sister that my grandpa made a harsh comment about my hair high lights. I just wanted something different. She told me, “You just grow up. You’re 20 years old and it’s YOUR hair so YOU get to decide what you do with your hair. Your grandpa doesn’t have to like it and he won’t agree with everything you do. Just like our parents didn’t agree with everything we do. Accept it. Don’t mean to sound harsh but it’s the truth.”
Why are men so skeptical about a woman’s choice in hair? My dad was the same way and wasn’t always pleased.