Can "should have done" express supprised truth?

Question

A young man asked a girl hanging out in a beautiful afternoon after work. But she trotted away with an old man in his 40s to play Golf. Below is the article:

He remembered those weeks of timid indecision, during which he had looked and longed and despaired of ever having the courage to ask her.

　　Dared he face the risk of being humiliated by a contemptuous refusal?

　　But if she were to say yes, what rapture!

　　Well, now she had said it and he was still wretched–wretched that she should have thought it such a perfect afternoon for Obstacle Golf, that she should have trotted away to join Henry Foster, that she should have found him funny for not wanting to talk of their most private affairs in public.

Here are 3 "should have done", but the things had happened, not an assumption. In the Chinese translation, it "should have done" express the boy unexpected / surprised those things and thought it was not fair.

I looked up this What are all possible usages of “Should have done”, seems not one mentioned this useage of "should have done".

Answer 1

The Cambridge dictionary offers several meanings for should. One of them is "use after that to show an opinion or feeling". Here is an example:

It's odd that she should think I would want to see her again

Looking at your sentence...

... he was still wretched– wretched that she should have thought it such a perfect afternoon for Obstacle Golf ...

In this case, the feeling is that he feels wretched.

Answer 2

"Should have [verb]" can express surprise depending on the context. Without the rest of this passage, I can't tell you if surprise was intended here, but here is an example where this includes surprise:

"Climbing Mt. Le Conte should have been easy, but William soon discovered he was more out of shape than he thought."

It is worth noting, however, that this only really expresses surprise because the "should have" is based on some preconceived notion (in this case that William was in-shape).