"Stack Exchange, Inc. does not discriminate in employment matters on the basis of race, color, religion, gender, national origin, age, military service eligibility, veteran status, sexual orientation, marital status, disability, or any other protected class."
Presumably they are legally required not to discriminate in these matters, in which case it's rather pointless to announce it. They don't specifically state that they wont kill you and harvest your organs - but I assume that they don't (although Oracle might)
Or if these are areas where companies are allowed to discriminate then they are hardly likely to say so on their job ads.