In the US (AFAIK it’s similar in other countries, but I’m primarily talking about US law) an employee using their position within a company to take money from the company to themselves is considered is considered a criminal action, which will commonly result in arrest and a criminal trial, with a possible jail/prison sentence upon conviction, and with conviction of such automatically disqualifying the person from many jobs. The common name for the crime is embezzlement, though the exact name will change based on local statutes and common law, and is a well-recognized crime that is commonly prosecuted.
But an employer using their position as employer to take money from employees to themselves by underreporting hours (either quietly or requiring ‘off the clock’ work), docking pay illegally, keeping money withheld from paychecks that should go to another purpose, or just deciding to pay less than they agreed to is not. It’s generally considered a civil action or a matter for a ‘labor board’ to handle before a civil trial. In the event that it happens to be illegal, it’s under a law that is very rarely enforced.
My contention is that all embezzlement should be treated in a similar manner, and that employers stealing from employees should be made criminal under similar principles to employees stealing from employers, and handled with at least the same severity. Employers who engage in wage theft should risk arrest, trial, imprisonment, and having a crime of violation of ficudiary duty on their record, the same as employees do. I don’t see how one can justify the current system, other than ‘the laws are written to protect people with power, and employers generally have more power than employees’.