As someone who grew up in the EU I believe that human dignity is an fundamental right, and that treating a person in a support role with basic manners is in the spirit of that right.
I have worked in places where customers expected some kind of service provided and the nastier behavior got rewarded the most.
While for some this behavior come naturally, I think there is also an element of conditioning to this behavior.
Also, people are not calling because evertyhing is great. Some level of frustration and anger must be expected in such a job. But my impressions is most companies don't train their workers to handle such scenarios.
In my last day in South America I spent about two hours cancelling my cable and even though I was very soft spoken and super patient (I was playing Mario Kart on mute so not really uncomfortable), but the customer support person actually CRIED to me because she would “miss her quota” if I cancelled.
I had no means of paying anymore (I cancelled my bank account the day before and was about to move to another country) so there was nothing I couldn’t really help her, so I fail to see how I deserve the treatment from the company.
America's paid by superPAC donor's laws seem to permit this, sadly