There are many people who believe, or effectively believe even if they acknowledge some innate differences, that people are essentially the same, and all differences between them can be explained by cultural, social and personal experiences. A paradigm which is sometimes, mostly by critics, called "standard social science model" (basically a polar opposite of believing that we are all born stratified into casts, classes, races, sexes... and that this stratification determines each person's fate).
If you adopt this paradigm, all inequalities must be a result of sexism, racism, or some other discrimination or failure on the part of society. It's seen as unfair and unjustified and in turn results in actions against that perceived injustice (legislation, shaming, protests, demonstrations, blog posts...).
And it goes deeper than that. Some people will say that beauty is a cultural/social construct, that obesity is a result of unhealthy food being priced lower than healthy choices and affects poorer people more (it doesn't btw). This pattern of conflict between being affected by circumstances vs having some innate qualities is very pervasive.