The word diversity has changed, acquiring a related but separate meaning. It is a political, not a scientific or literary meaning. If you don't know that, and insist on using the word as if it has not moved, you will seem to be a bigot. In addition to the previous meaning of "variety, multiplicity, heterogeneity" it now means "showing conscious respect for previously disadvantaged groups, especially African-Americans." You will not find this meaning if you look in dictionaries (though this will be coming soon - modern dictionaries are descriptive, not prescriptive and don't care what people think a word should mean). Yet if you google "diversity" and look at the autocompletes, you will see that the new meaning is already the more common one in popular culture.
Therefore, when some Ohio senator tweeted that diversity is not a strength, assimilation is the strength, he was assailed from many sides. His statement, according to the old meaning, is not only true but blindingly obvious. Only a fool could disagree with the first half of that statement. The second half - well, it's going to depend on what one means by "assimilation," but I'll bet I would agree with him.
However, his critics took him as if he was using their more modern and fashionable meaning, as if he was saying "It's not important to show respect to black people, or gays, or women, or Hispanics, or whatever. Keeping them invisible and powerless is okay." Do those attacking him not understand what he meant? I am tempted to say that they understood him entirely, but they want an excuse to attack him, and to insist that their meaning - their culture, their fashion, their signalling - is the real one. There is a real boot-stepping-on-a-face-endlessly nature to this. It is Newspeak, where only the special ones understand, and they get to punish those who must be evil because they aren't woke. Liberalism is sustained by fashionableness, after all. I have no doubt whatsoever that this pretending to not understand is a fair accusation against many in The Resistance.
And yet...I am not now coming of age with words as they are currently used. I am old, and my reading and culture ally me with generations prior even to my own. I don't really know how thirtysomethings hear the word now. They might not be pretending to misunderstand (as one of the nastier critics, John Podhoretz clearly is) that use of "diversity;" they might actually think there are two meanings, and have leapt to the conclusion that because it's about politics, the political meaning is the true one. Some are dishonest. Some are indoctrinated. I cannot discern between them.
Additional note. Most of my black friends vote consistently Democrat, but many are not especially political, or are at least not public about it. Those few who adopt more of an advocacy stance are very liberal, very confrontive. I notice that they uniformly pronounce the word "die-versity," and absolutely only mean black people, not gays or folks with disabilities or Asians. The nuances of that are going to be clearer to an African-American who keeps up with politics than they are to me.