Hiring based on gender and sexuality means you purposefully pick lower skilled workers in order to fill a diversity quota.

Incorrect. It means that you pick the best candidate, and when they're equal you don't just choose the white man like we always have in the past.

I'm a straight white man. I have no issue with diversity because it makes everyone better.

Every worker regardless of background has a unique view, and can provide creative solutions without having to be reduced to their genders, sexuality, skin color.

Sure, that's true because everyone has a different background. However, a straight white Christian man would likely never think of some of the things a gay Muslim would think of, because they have faced different issues and been taught different things.

For example, there's an issue with IQ testing, where the tests were designed for typical western education. However, different cultures can be better or worse at certain questions just by how they're phrased. Some cultures may think of something geometrically. For example, all math by the ancient Greeks were done with shapes, not numbers. They would solve math problems in totally different and unique ways than a typical modern day western educated person would. They aren't less smart for it. Their brains were just wired differently because of the way they were educated.

Not every person thinks the same. Cultures, education, oppression, trauma, pleasures, and everything else effect how you think and you you'll think of. Diversity in thought allows us to take advantage of this as much as possible.