Yes, they actually do. They’re probably conservative dickheads. They know that pink hair is code for “I am a tolerant and kind person; I might be gay but not necessarily; I support counterculture ideas.”
They hate the counterculture ideas. They don’t hate the color pink. Covering it up with a terrible wig makes it about something else.
Or anyway, so they think. What they’ve actually done is given her an opportunity to start conversations about the pink hair.