That's why I love CG, we know most of the umas as cute goofy goofballs that run fast (gross oversimplification but you get what I mean), but we can't forget that they're actual people too in their world (obviously duh).
They each have their own feelings and living in a happy only world is for dreamers, the negative is always around the corner and we're seeing both the top of the ups and lowest of lows of the characters and honestly, I much prefer it this way.
Hate and conflict is as natural as love and unity, they're both 2 sides of the same coin and Cinderella Gray shows it to us.
Sure, in other Umamusume IPs there are some dark moments where characters can fall into depression due to a fracture or something like that, but we rarely get intersocial conflict like on here and that's what is really refreshing to see.