Is colored hair really that unprofessional?

If someone had all the right experience and qualifications, can something as arbitrary as unnaturally colored hair really be the limiting factor?

I want to dye all of my hair turquoise blue. My roommates say that’s a horrible idea since I’m currently looking for a full time job. I don’t really understand why colored hair is considered so unprofessional. Would having unnaturally colored hair truly keep me from getting a professional job and if so, why exactly is colored hair considered so unprofessional?? It’s simply an aesthetic choice in my opinion.

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