Following your rationale, any situation where the parties involved have uneven bargaining power would amount to extortion.
Extortion involves the illegal extraction of money, property or privileges from another. There is nothing illegal about requiring your employees to abide by certain rules in order to keep receiving their paychecks.
No. This case involves property and sphere of the workplace boundaries. The employer is attempting to exceed his rights and usurp those of his employees. The example of the "friendly visit" proves the heinousness of the infringement. The economic concerns in combination with the usurpation of the employees rights, make the employer's uneven bargaining power extortion.
Organized crime pulls the same thing. The offer a protection service. The shop owner "agrees", because otherwise some vandal will torch his shop.
" Extortion involves the illegal extraction of money, property or privileges from another."
Surely your omission of "right" was simply an oversight.
"There is nothing illegal about requiring your employees to abide by certain rules in order to keep receiving their paychecks."
The rules are limited to the workplace, or they are not valid. In this case the extension of demand outside the sphere of the workplace and the employer's right IS extortion.