Googling for questions and associated discussion, is one way to look for common conceptions. So I googled "what color is water"[1], and the top snippet of "Is water green or blue?" was this gem[2]: "Water isn't inherently blue; our eyes and brains interpret water as being blue because water molecules absorb reds, greens, oranges, and yellows—thus leaving only shorter-wavelength blues and violets unabsorbed to reflect back for our eyes to see." Lol.
Maybe it's like bluebirds, which are popularly scientifically said to not actually be blue because the way they're blue comes from a refraction effect.
There are conceptions around color being an inherent property of an object, independent of the light coming from/to it. "The book is purple". Turning off the lights doesn't mean the book has changed color, and now is black. And it still is a purple book, even when under red light it looks red. Sort of "object's potential color if lit with white"?
If one thinks an object is the color it reflects, then add confusion about refraction, and one might easily get to "it looks blue but really isn't".
Science education echos stories, and sometimes those are less than wonderful. Like tabloid journalism narratives, missing the point and leaving readers confused and misled. As with "color from refraction, constructive and destructive interference". IIUC, that interference is mere description of wavelength-dependent differential bending - you still need to absorb the colors you don't wish emerging. But emphasizing "it's not pigment color, it's structural color!", rather than their similarity, can parse as reflection/absorption vs refraction, and conceptually interbreed with real vs apparent object color.
Stories like [1]. The "constructive interference" is "cancelling out" wavelengths, which "is why your eyes perceive" blue. Rather than say, here's one of several mechanisms for pigments to color objects.
[1] https://www.google.com/search?q=what+color+is+water [2] http://crosstalk.cell.com/blog/why-is-the-ocean-different-co...