1.
Porn. Does porn provide an accurate image of what sex is like? No. Porn is two people fucking in uncomfortable positions as fast and hard as possible to make it look good on camera. Does somebody get hurt by porn? No.
Porn also defines unrealistic new standards: It shows what sex is supposed to be like. It shows how you are supposed to look like. Actual humans and and actual intimacy have no place in the universe of porn.
For example: Since a few years there's the craze for women to ask for plastic surgery so their labias are as small as the labias of porn-stars. Why? Because porn has defined a new beauty-standard.
https://en.wikipedia.org/wiki/Labiaplasty
Porn moves the definition of "normal" away from things that actually exist and towards things that only exist in scripts and movies, thus making them real after-the-fact. You are no longer a human, you are a canvas to depict the latest cultural craze.
2.
Celebrity culture. We are long past the point where we treat celebrities as human beings with a right to a private life. What do we do if some paparazzi reveals something private and embarrassing about a celebrity? Do we look at the headline and say "No, it would be really impolite to intrude into their private life like that?"
No. We eat it up. Because those celebrities OWE us an insight into their private lives. If they don't want these things to become public, why did they choose to become famous?
We consume celebrities and with this consumption we justify treating celebrities like objects that exist to our amusement instead of actual people. That is dehumanization.
3.
How would you feel if the sex-doll had your face? Your daughter's face? Would you feel uncomfortable around a person who fucks your likeness whenever he feels like?
Why would you? He is not hurting you! All he does is connecting your face with the sensation of having cheap, emotionless sex. How could this possibly have downsides for you?
How could a sex-doll with the face of your under-age daughter possibly have downsides?
4.
"Does using email dehumanize the mailman?"
I want to give you a quick example of corporate culture.
In Germany, the company-department responsible for administrating workers is called "Personalbüro", "office of personnel". The worker is by name a person.
In the US, the name of that department is "human resources". The worker is by name a resource, an object.
You are free to read up more on the topic whether the human counts as a human when in the workplace.
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