"The colors of the shoe are violet and pink."
Translation:Màu của chiếc giày là tím và hồng.
I believe it's because màu is earlier in the sentence. The answer they post is like saying "color of the shoe is purple and pink". You wouldn't say "color of the shoe has purple and pink" because you're talking about what the color is, not about the shoe. You could say "chiếc giày có màu tím và hồng" to say the shoe has pink and purple. That's when you would say noun has color x instead of noun is color x.