Though I personally did not work in call centres here in North America, many of myfriends did. The employees have a basic pay and performance bonus based on calls handled and or business generated.
Same is true for any industry. What is wrong if an employer is expecting accountability from his employees? THis is imperative in today's cut throat and challenging economies. People are hired and fired in minutes in this part of the world, if performance is below expectation.
At the same time, i strongly beleive that the working conditions shall be human for any employee, whatsoever may be the industry.