I understand that red may have already been taken by strawberry. But why blue? And why in particular such an artificial, Star Trek color of blue?
Similarly, why did raspberry get stuck with this instead of strawberry?
Different shades of red were used for watermelon (lightest), strawberry (second lightest), cherry (darker), and raspberry (darkest) to distinguish them. When the coloring used for raspberry was banned by the FDA for being carcinogenic, some brands switched to blue to distinguish this flavor from the other red fruits, and it stuck.
It's worth noting that blue raspberries, or western black raspberries, do exist.