I think that's a bit of a simplistic way of looking at it. There's an easy explanation of why this approach exists though, if you agree with the following statements:

- Race, gender, sexual orientation, disability etc. do not generally affect an individual's skill as an employee

- People from certain groups are under-represented in the industry

- Under-representation generally reflects an underlying problem somewhere, because one would expect various groups to be represented broadly in line with wider society

- One of the problems that can cause under-representation is an existing bias in an industry, which can discourage other members of a group

- One of the approaches to solving this is to help ensure that those groups feel comfortable in the industry

- One of the approaches to helping them feel comfortable is to ensure that communities are inviting, open-minded, and aware that things they say or do may upset or discourage other people, even though they are do not find those things offensive themselves.

It's about observing a trend which seems wrong for various reasons, and attempting to help solve it. I don't doubt for a second that many people go completely overboard on this issue, but outright rejecting any attempt at using, say, gender-neutral language in open-source projects just seems to go completely in the other direction.