Oh, tsunderes can be very cute.Shy with their feelings, very precious when they finally crack and open up. That is, if they know where to draw the line like a decent hu...like any human being should be able to do. "the type that use physical violence like breathing" is just a fiend with a personality, which went astray down a bad way. People that tend to use violence even against their "beloved ones" are no good news and no good spouse material. Elna didn't show to be that violent, yet, but MC already mentioned that she tends to use violence in most situations to get her way. She even snapped last chapter because of a slight provocation and tried to escalate the situation to give Silver a good beating.
@lupus_in_fabula told us how it is. She is exactly that, a self-righteous person. That is the impression I got of her. "Mother knows best, so shut up." End in a relationship with such a person and you are in a relationship with a person, that will never see you as his/her equal counterpart. Those are enough reasons to not like her and the way she messes everything up is very good reason to hate her part of the story.
Though I do like her not over-the-top sized breasts. It doesn't always have to be EEE-cups. Viva la diversity!