The ultimate crime against people: dehumanization?

I think you are correct that prejudice and discrimination fall under the umbrella of dehumanization, but I think dehumanization is the result of a deeper root. The root of the problem is a lust for power and control, often mixed with corruption and mental illness and deep-seated insecurity. This root is what leads people to dehumanize others.

Dehumanization is worse than death is as an old trope in debate.

Simple refutation: death is permanent, dehumanization may be transient, one is an end the other may be ended and so on.

Then you can go on listing examples of people that have been dehumanized contributing to society and leading fulfilling happy lives while the dead are...dead.

Anyway, like I said that is an old debate trope and was routinely encountered for some time.

The next step after COMPLETE DEHUMANIZATION is always genocide.

I recently watched man-on-the-street interviews in which numerous people are rejoicing and in full support of babies and toddlers being killed in an ongoing genocide.

A book I recently read said genocides and other atrocities are ignored or supported because there is profit to be made and criticism would get in the way of that.

You pretty much covered it in your OP.

Dehumanization allows people to rationalize atrocities by reducing their victims to objects. It’s easier to commit harm against an object, like a chair, than a human. Over time, consistently referring to or thinking of someone as less than human makes it easier to see them that way, reducing cognitive dissonance and justifying harmful actions.

To your final question: Crimes against people may not be born out of dehumanization, but they are often rationalized that way. In other words, crimes can be driven from various motivations -- greed, power, ideology, opportunity -- but dehumanization frequently plays a role in justifying or enabling those actions to be carried out.

"I'm a human being godammit! My life has value." https://www.youtube.com/watch?v=_RujOFCHsxo

This is exactly why Israel referred to Palestinians as human shields. They were no longer beings, they were just shields, easier to slaughter.

Have you seen the Black Mirror episode Men Against Fire?

"examples: objectification of women and holding racist stereotypes"

wut?

Women OBJECTIFY themselves. Just because 7 ugly feminists aren't getting laid doesn't mean they can yell about all women being sexified. Since the dawn of all recorded history, women want sex for kids and WORK to attract mate. It's kind of thing.

Stereotypes: a widely held but fixed and oversimplified image or idea of a particular type of person or thing.
WHERE do you think stereotypes COME FROM? No one invented them, they simply exist. Every time I visit a section of town of differing races, I can easily SEE stereotypes, existed, right before my very eyes, and those races are fine with it. As are most non-political correctologists and reality based anti-SJW humans. Life is what it is.

Reality is reality. It is not going to bend for someone's wishes of how they want things to me. Reality always wins out in the end.

Want to stop hurting humanity? Talk to me about eliminating COMPETITION: Sports, business, mating, all of that... we can REASON past competition, right? Yeah, no. Just more wishful thinking - never gonna happen. COMPETITION causes all manners of conflict, and everyone embraces it, even pays hundreds of dollars for tickets, just to practice hating others for zero logical reason, because they like another team based on geographical location. THAT is insane. And makes mega billions also.