Diversity. You keep using that word. I do not think it means what you think it means. Today, people who call themselves liberals insist that America (or the West in general) is not diverse enough. They claim that we are not diverse enough with respect to gender (no really, there are more than two genders. Okay.) or ethnicity or sexual orientation, or religion. The problem with their claims is actually two distinct problems: (1) that's not really diversity and (2) it goes against actual liberal principles.
Real diversity means diversity of thought. The way liberals classify diversity by identifiable categories like race and gender is literally, superficial. Real diversity - the diversity that makes America a great country - is diversity of thought. Making sure that society is a certain percentage gay, a set percentage female, an exact ratio Muslim and an equal proportion of African American, Hispanic, Asian, White or otherwise does absolutely zero. The ultimate question is what does that offer? Next to zero benefit will arise from the supposed fairness this offers. I'll save the fairness argument for another time. Instead let's look at viewpoint diversity.
Tackling a problem with viewpoints from the left and right, from a passive or aggressive viewpoint, a scientific and humanitarian perspective concurrently, allows for a greater possibility of a comprehensive and successful solution to a problem than one developed by a visibly diverse but otherwise homogeneously-thinking group. Without ideas being challenged they do not get tested before being put in place. That's a recipe for failure. But that's exactly what social justice warriors want to happen.
This is where the other problem of incongruity with liberal principles comes into play. As a reminder, here's what classical liberalism actually is:
Classical liberalism is a political philosophy and ideology belonging to liberalism in which primary emphasis is placed on securing the freedom of the individual by limiting the power of the government.The philosophy emerged as a response to the Industrial Revolution and urbanization in the 19th century in Europe and the United States.It advocates civil liberties with a limited government under the rule of law, private property, and belief in laissez-faire economic policy.
"Securing the freedom of the individual by limiting the power of government". Social Justice Warriors want the government to impose equality on everyone. And by that they mean equality of outcome, not of opportunity. They mean equality of visibility based on visual identifiers. That comes at the expense of ideas. There will be no diversity of ideas under that model and that means that individual freedom of thought is superseded by these visual markers. That represents the death of liberty and true classical liberal ideals.
The problem for the country is that leftist leadership are adept at using that social justice warrior thinking to increase the preponderance of that sort of thinking. And while they have had a lot of success at doing that, they have simultaneously tried to tamp down individual thinking within these identity groups; if you are African American you have to be a Democrat. If you are gay and are a Republican you need to have your head examined. If you don't use the pronouns people choose to identify themselves by, you are a racist, misogynist homophobic neanderthal.
The synergy of progressive liberalism with the consolidation of superficial identity groups is a recipe for totalitarianism. Classical liberalism it is not.