This is perhaps a broader explanation than you ask for and is specific only to the United States, but here many laws (and corporate policies) recognize that specific groups have faced and/or continue to face discrimination and are designed to promote equity over equality.
Equity Over Equality
For example, in the American workforce, it is legal for older employees to make fun of the quirks and stereotypes of Millenials and Gen Z workers but the reverse is explicitly, specifically illegal. Why? Because workers over 40 have continually faced discrimination in hiring, promotion, and retention in the American workforce. As a vulnerable minority, any bias based on age–along with race, ethnicity, gender, sexual orientation, national origin, and religion–is illegal, a conscious choice made by society to address the history of discrimination and lack of opportunity among these groups.
Why is it okay to make jokes at the expense of White people and not Black people (or Brown people. LBGT+ people. people with disabilities or chronic illnesses, Jews, Muslims, immigrants, and others) in America? Because members of these groups have historically faced discrimination, housing and employment bias, unprovoked violence, and exploitation by those who have held power of them–the White, Christian majority of the nation. These groups continue to face many of these forms of oppression at the hands of the majority whether you see or experience it in your own life or not and society is finally coming to acknowledge this fact. The country is finally beginning to work towards equity for its members and this is an awkward, slow, sometimes painful, and often divisive effort. It is believed that equity will eventually lead to true equality.
Don’t Punch Down
This is all complex and nuanced; often the most well-meaning efforts fail to achieve their goals, and often corporations simply make halfhearted gestures to “keep up with the times.” That is just where we are now. The easiest (and most oversimplified) stance can be summed up as “don’t punch down.” Don’t go after the weakest among us, not for personal gain, not for humorous effect, and not to protect the feelings of those who have never faced discrimination in their privileged lives.
It Ain’t Perfect
America isn’t handling all of this perfectly well, and no organization is, but it is a step in the right direction to protect vulnerable and historically oppressed groups–even at the expense of these groups who have never been vulnerable and never felt oppression. Seeing other groups given their freedoms and protections may feel like yours are being taken away, but only if you’ve never had to share them. There is, there will be, enough for everyone in the end.