We don't write a lot of "Dear John" letters, but this seems like a good opportunity. As in, "Dear John, it's not you, it's me. I just couldn't survive in a monoculture that stifled all differences. No wait, it's not me, it is you. I quit. Sincerely, A Former Employee."
You're definitely in great danger of creating a monoculture at your company. Take a step back. How many people on your team look like you, act like you, have the same background as you or were friends before you worked together? How about in your company as a whole?
A monoculture is dangerous because you get a narrow perspective. It limits the growth of new ideas. Meanwhile, the world goes on outside, growing broader perspectives. Your team or department might feel easier for you, but is your company served by a narrower culture? Once you've taken stock of yourself and your team, interview the full slate. The extra time and effort could be worth it.
Your HR department probably gave you this challenge because someone else foresees this risk. Rather than getting what you want, or what's "good enough", focus on getting what's best for your team and your company.