Too harsh?

Okaay soI'm working an an OC in Ponyville story (cliche yes I know). The main character is meeting Rarity for the first time, and he has a huge prejudice against ponies from the higher classes, specifically royalty and minor nobles. There is a reason for it, but I want to know if the first bit of dialogue between them is too harsh. It follows after the break.

“So you and Rainbow Dash are…..related?” Rarity raised an eyebrow at the Earth pony sitting beside her. He had turned back to the pool and was watching the young fillies play.

“Not really,” said Cinnamon, barely moving his lips.

“I’m not sure I understand, Darling. I could have sworn your, um….”

“Sister.” The word came out short, almost as if Cinnamon was trying to bite it off before it could escape his lips.

“Right, sister. I heard her call Rainbow Dash her aunt.”

“Yes…” The drawn out sound of the word reminded Rarity of an old play she designed for, where the actor playing a snake would utter the same long hissing sound at the end of each line. She looked at Cinnamon closely. Although he had not noticeably moved, the set of his shoulders and the way his ears laid a little flatter on his head warned her she had said something she shouldn’t have.

“Do forgive me for prying, I meant no offense. It’s just that Rainbow Dash never talks about her family, so the girls and I were starting to get a little worried that she had none.”

“She probably didn’t want the whole slew of questions that always follows having to explain things to nosy individuals.”

Rarity’s mouth hung open, the heat rising to her cheeks at the sheer venom in his voice. Not even Applejack had been this rude; even during the height of their misunderstanding there had always been a forced politeness between the two of them. This, however, was something she had not experienced before. This Earth pony hated her, and Rarity could not understand why.

“Excuse me, Cinnamon. I was merely trying to get to know somepony who happens to be somehow related to one of my best friends and I-“

“Oh come off it. I know exactly what you were trying to do, and it isn’t going to work. Don’t try to give me that ‘I’m just a caring friend’ crap. All you and your kind care about is yourselves. You aren’t tricking me into believing that whatever you say isn’t some ploy to take advantage of me, or anypony else.”

“Well! I never-“

“What? Never had somepony call you out? Never had somepony who is smart enough to see your ploy for what it is: a desperate attempt to control the lives of those around her? Thought not. Why don’t you go back to Canterlot or Manehattan or wherever you come from? Go make art or whatever other useless thing you do and leave the ponies who actually contribute something to society in peace.”

Let me know what you guys think. And don't worry, they really aren't related.