It's certainly true that suggestion can change ones perception of wine (or any flavor), but I don't think it's clear that it's the primary factor.
The original study finds that the terms we use for flavor (partly) encode the tuple of flavor and color. That is, given two identical smelling / tasting liquids, subjects will pick different vocabulary to describe the flavor when the liquid is red vs clear.
Of course, you're not supposed to be an expert. But still, seems like a hypocritical thing to make fun of someone else for.
Why is the color so important? Mostly because it's visible to us noobs.
So what depends on why things are different colors. For instance, red velvet cake is just vanilla cake dyed red with food coloring. In that case, there wouldn’t be a difference in taste. On the other end, vanilla bean ice cream has black specks distributed throughout from the contents of the vanilla bean itself. If you substituted black pepper, it might look the same but it would not taste the same. As Niksko explained, red and white wine are different due to differences in ingredients and different processes which impart different flavor and color.