We don't know.What color are black holes?
You don't know that. We can't access information inside black holes.They're really not black; they're not really any color.
This is like asking "what color is farming?" Farming being the idea of an activity makes it not defineable by color. Farming still exists, however. How do we know? Because people do it.
You are conflating two different meanings of "exist." Farming and morals are just arbitrary designations for some of what people do. It is the people which exist as things in and of themselves.
Morals as something people do is not a problem. Morals as independent things in and of themselves is an issue.