I don't think I would say that it's a backlash. But there has been a real danger in the tendency to want to claim privileges or rights for some people based on some kind of marginalised or oppressed status.
What this does in essence is set up another hierarchy of value, sets of people with special protections. Perhaps it's been profoundly naive not to think that over time this would create its own, new set of privileged people. Whether they are the people who were previously marginalised and are now able to use the system to their own advantage, or people who are able through power or advantage to get themselves included into categories they aren't entitled to.
In hindsight, this was a problem some people gave warning about back when we were seeing a lot of special named protected categories in laws and constitutions, hate crime laws, affirmative action policies etc. That together this direction could be problematic, that it was creating essentialist categories of people. At the time the general response of progressives was that these were overblown fears, probably coming out of bigotry. The one that really seems naive now is the idea that people from a marginalised background would never be in a position to take advantage of such laws and protections in a way that was detrimental to others. In fact there almost seemed to be a sense that such people would not behave that way because of some kind of solidarity.
What we seemed to be really seeing was the beginnings of identity politics, which have been completely toxic. Even women's rights, which ought to be a material category, have been brought under the identity politics tent in many cases.