I personally have no knowledge of the Contributor Covenant history nor any opinion on whether adopting this particular text is right or wrong, but since the explicit list of protected class triggered a discussion, I wanted to highlight that the Coq community has adopted (several years ago) a Code of Conduct from another source (see coq/CODE_OF_CONDUCT.md at master · coq/coq · GitHub) which contains:
We strive to be a community that welcomes and supports people of all backgrounds and identities. This includes, but is not limited to people of any origin, color, status, educational level, gender identity, sexual orientation, age, culture and beliefs, and mental and physical ability.
It has a few differences: the list is explicitly “not limited to”, because of this it makes sense for it to be shorter, finally it includes “culture and beliefs”.
(Also, FWIW, for me the term “protected class” is evocative of the USA non-discrimination legislation, which has a lot of holes and has led to a lot of actual discrimination, e.g. against same-sex couples, being legally protected… So not really a good model to follow… Apparently, Google agrees with me that this directly comes from US legislation because when I search for “protected class”, the first result is https://en.wikipedia.org/wiki/Protected_group.)