Diversity is one of those feel-good, virtual signaling words that the left loves to throw around. Along with tolerance, inclusiveness, and sustainability. Words which make the person using them feel good, functioning as stirrups to keep them firmly perched atop their moral high horse.
Diversity refers not to a variety of ideas, as any conservative speaker trying to deliver a lecture on a college campus can attest, but instead to identity markers of skin color, race, ethnicity, gender, sexual preference, traits which most Americans see through without discrimination. As Martin Luther King, Jr. spoke of judging people by the content of their character, not the color of their skin.