I made the correction, i.e., the Dutch Colonist generally opposed slavery. Although many owned slaves, there was never the demand for the numbers of slaves in the colonies settled by Dutch, Swiss and Danish.
Reading accounts of house holds, it was very rare to find a household owning more than a few slaves.
In only 25 years, they couldn't have had very large numbers compared with what came later. In 1664, the English took over. I still question that Dutch colonists generally opposed slavery. If they did, then wouldn't they have stopped the influx of enslaved people completely? The dissertation says there was "an active demand" for enslaved blacks, even though there was also a strong opposition. The opposition can be strong without being general throughout the Dutch colonists, and one doesn't need to own slaves to support the system.