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.

That is not what is happening, and your scenario cannot happen unless by equal you mean based on a very shallow measurement. You'll never find two people who are equally good. It also doesn't say the program is for women, non-binary or skilled men. It excludes men entirely.

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.

I disagree with this view. "Only people of X can produce quality X" is just shallow thinking, and can in fact be used just as much as a counter argument like "only men can make quality games for gamers who are mostly male, so we should hire mostly men". A straight white christian male can absolutely have similar views and ideas to a gay Muslim.

Also, if you're hiring a gay Muslim over someone else just because they are gay and Muslim, how do you think that makes them feel knowing this?

But more importantly, what does gender, sex and ethnicity contribute to a team of programmers, which is half the workforce of gamedev?

In hiring, when asking for expert opinions, when looking for quality, the best gender is always "any". The best sexual orientation is always "None of my business", and the best race is always "Human"