You're very likely right there's no causation in that direction, but it seems entirely possible that we experience red as a vivid color in part because noticing blood is evolutionarily important.
The article likely distinguishes between simply having colors versus evolving colors specifically for sexual selection - fossil evidence can show dinosaur coloration but determining behavioral purpose is much harder than observing living fish species.
Perhaps because it's not truly known.
> The discovery "suggests a more colourful Jurassic World than we previously imagined,"
-- from your link