It’s called dark because we can’t see it, and matter because it interacts gravitationally. There is nothing wrong with the term and the model of it even if we don’t fully understand what the hell exactly it actually is and most importantly why it actually is. It’s literally how science works. We don’t know what the hell quantum probabilities and all the weird particles and fields mean on a metaphysical level either but QFT is the most tested and predictively powerful theory of science ever made. Is it complete? No, we may even never find the theory of everything. But it doesn’t make our discoveries wrong.