What is probably being referred to here as a "white utopia" is an observation about Oregon's early black exclusion laws. Unsurprisingly, early settlers to Oregon brought with them the politics of slavery.

"Founding the Far West," by Alan Johnson is probably the best discussion of how the foundation or the Oregon Territory (and later state of Oregon) were built on the local reactions to slavery. Johnson points out that many of the settlers to Oregon were non-slave holding farmers from Appalachian border areas like Kentucky, Ohio and Missouri. These settlers were not supportive of slavery, but not because of its human rights implications, but because they saw it as unfair competition to smaller landowners who could not afford slaves.

A territorial judge, in a case regarding a fugitive slave, put to words what would seem to become the regional perception of slavery. It was incompatible with what he described as the nature of the Oregon community. "Establish slavery here, and (y)ou will turn aside that tide of free white labor which has poured itself like a fertilizing flood across the great States of Ohio, Indiana and Illinois."

The point wasn't to ban black people or slaves because they were equals, but because they were cheap competition.

Johnson also points out that later, when Oregon was putting together its constitution, one of the points that all could agree were "...in absolute agreement about (was) the need to preserve homogeneous populations, and that was race."