The USLC system is a replacement for that union contract, so the employees do not need a union contract. Employees do not need to get a union contract to get a grievance procedure. The employer has already provided it. Today a majority of union units are organized because there is no grievance procedure. Employees don't feel they're given respect by the employer.
Employees feel that they're being demeaned.
Employees feel there is no legitimate outcome for their needs or wants. So wages are not the major point of union campaigns any more. Less tangible issues are the focus these days. Employers still believe that if you pay employees enough that they'll be happy. The unions are catching on to this and are using this as a big issue.