He doesn't say, "we don't kill, and if you want to live here you'll have to respect that," he says "Killing is wrong
Actually, he has said exactly that, many times, starting with IIRC Titans #1, when he notes that she really DOES have a bloodlust (She's zapping Gordanian Slavers at the time, but even so) and that that's not how things are donw on Earth.
If Dick were living on Tamaran, I'd expect him to be forgiving of their social standards and attempt to fit in there.
Kory reminds him he's full of shit and Tamaran is no stranger than Earth, and rightly so, but she shouldn't have to.
Sorry, no, she is as dismissive of Earth culture as you are saying Dick is of Tamaranean. She's saying that passion should overcome everything, which is certainly A point of view, but by no means a particularly valid one.
Her statement that "none of our problems are caused by hiding our feelings" may be accurate, but it's reasonable to assume the inverse is true, that a lot of their problems ARE caused by their INability to control their emotions. Tamaraneans are all about the passion, and that works for them, but it's not in any sense inherently better than Earth. They are direct, and open and also capable of fairly terrifying violence, just because they make good smoochies and are naturally incapable of emotional control does not give THEM any reason to claim they're way it superior to Earth.