I think like most "weird Japan" articles this one is being mischaracterised somewhat.

It is often somewhat difficult in Japan to get your legal entitlement when leaving a so called "black" company. They might not easily pay out your remaining holiday, or they might use "power harassment" to otherwise make your exit process difficult.

So I can see that a company like this, while not providing legal services, removes the possibility of applying harassment to coerce employees to stay a bit longer or not take their full legal entitlement.