"Correct" is a strong word, it works for their show because you're seeing it through the protagonist's eyes who is absolutely loving the situation when compared to his dull office job. The colorful aesthetic there serves as part of the storytelling. However, choosing to just not make blood look like blood for everything only serves to undermine the violence shown. People talk about the dangers of becoming decensitized to violence through media, but imagine if media doesn't even show to grousom results of said violence what that could do to people's perception of it in real life.