Sure, it could be, you can define "preference" as basically anything, but it just loses its meaning if you do that. I think most people would think "56% prefer this product" means "when well-informed, 56% of users would rather have this product than the other".
Couldn't this be considered a form of preference?
Whether it's the type of preference OpenAI was testing for, or the type of preference you care about, is another matter.