Protecting bad employees is not really what game industry unionization is all about. Its more about standardizing job titles and accreditation, like film industry unions.
Admittedly I assumed this thread had devolved to general development unionization. If game industry employees are valuable, not easily replaceable, limited to only a few companies, and can't easily repurpose themselves then unionization has value.
Unions in Hollywood place a useful role of insuring proper credit and arbitrating when there is a dispute. Some game publishers have tried to avoid credits, partly to make it more difficult to know which employees to poach. But I have seen credits sorely abused in some instances.