No, it isn't. It's about irrational prejudice and discrimination on the basis of biological characteristics and excusing those things. Which is why, for example, this "diversity officer" is so sexist and racist and remains in her position. Even calling for the murder of everyone of the "wrong" sex and "race" is entirely within the boundaries of "diversity". She's more prejudiced than most people who talk about "diversity", but it's a difference of degree only.
Even at the most moderate possible end of "diversity", it's still solely about whatever characteristics the speaker thinks define people. Usually sex and/or "race" but it could be anything. Sexual orientation. Age. Sometimes even unchosen things that aren't biological, like what region of the country a person grew up in. But almost always biological because that's what attracts simple irrational prejudices.
It's another politically motivated use of a word with a different meaning to the true meaning and it's another way to reinforce the idea that everyone is defined by whatever unchosen characteristic the speaker thinks is of paramount importance because it contains and requires the assumption that everyone with that characteristic is the same. "They're all the same" is the bedrock of irrational prejudice when it's applied to all people with an unchosen characteristic. There may well be more diversity between some individuals who happen to have the same sex, "race" or whatever than between some individuals who happen to have different ones. But that idea is anathema to the "diversity" people because it treats people as people and not as "groups" defined by whatever unchosen characteristic those people deem to be of paramount importance.
There is, for example, a great deal of real diversity between me and Jeremy Corbyn or between me and David Cameron or between me and Lord Sugar or between me and the Duke of Westminster. Rather more diversity than there is between me and many of my coworkers, most of whom aren't the same sex as me.
