My problem is not Rhysand being upset with Nesta. Half of the time he has a right to be upset with her. My problem with Rhysand is he ends up either screaming in her face or threatening to kill her (even if he wouldn't actually do so it's still a very aggressive statement to make to someone who is attached to your family whether you like it or not) and if he isn't threatening to kill her then he's threatening her with some sort of physical consequence. It also doesn't sit well with me that he finds some satisfaction in her being afraid of him at times.
That is where Rhysand's toxic traits come out and that is where I have issue with him.
Nesta is not perfect - not even close - however Nesta is around 25 years old? She's still learning a lot about herself and how to heal and change for the better. She's still adjusting to life of the Fae just like Elain. Feyre is even still adjusting although her circumstances have made her somewhat quicker to adapt.
Rhysand has been alive for centuries. I will always respect his character for what he went through with Amarantha and what he did to protect his friends and Velaris. He is allowed to have traumas and make mistakes. However, I would expect more maturity in communication during disagreement and conflict, especially when the person you are having that conversation with is going to be within your family circle.
Nesta is Feyre's sister and Cassian's mate. Whether Rhysand likes it or not Nesta is most likely always going to be somewhere within his life. Feyre and Nesta have their own understanding that they are working on. Cassian is her mate and she has claimed him as such at this point.
Rhysand does not have to agree with Nesta or even like her but he needs to find ways to get his points across that still show her basic respect without relying on her being afraid for her physical safety or saying things to kick her down.
And before anyone jumps down my throat: Yes, I am fully aware Nesta has purposely said awful things to hurt others but the whole point of ACOSF is Nesta recognizing her flaws and wanting to try to change for the better. Everyone is all "People need room to grow." And can't even give a fictional character the opportunity to do so.
Anyway, that's just my opinion I needed to get out somewhere.