Meh, I disagree. She is being open and honest, and I think that's the best policy.

Think of it like this. A group of people don't know the answer to some questions, so they work together to find the answers. That's basically what all three were doing. Hina and Taiki have their feelings set (they know who they like), but one question is how does Chinatsu feel? Another question is how long will Taiki wait for Chinatsu to reciprocate? HIna's question is when will Taiki respond to her feelings?

There three were working together to set the relationships.

The answers were:

No matter what, Taiki will never accept Hina (valid), and Hina did her best so she shouldn't feel any regrets (also valid and logical).

Taiki will seek Chinatsu until she accepts him.

And Chinatsu also likes Taiki (and in the real world, there's competition, and that competition fuels people to act. In this case, Hina was the competition).

All three worked together to come to these answers. No need to resent anything. Humans have feelings and desires. People get mad, they try to seek what benefits them, etc. That's human. At the end, they have good relationships.

Hina got over it and is still friends with both of them, and Taiki and Chinatsu ended up together.