Is she right to be picky about the ring?

Getting engaged is a huge decision and for the person picking the ring, it can be extra stressful.
What style do they like? What metal? Stones? What size is their finger?
One bride-to-be has sparked debate on Reddit's 'Am I The A**hole?' thread after her fiancé got annoyed when she didn't like the ring he proposed with.
To be fair, it wasn't as if he had nothing to go one, the poster explains in great detail what they had discussed previously:
"We had talked about marriage before & i showed him a few pictures of rings that i liked & that were my style & told him my ring size which is an 8."
"I do like slightly bigger diamonds cus i have chunkier fingers & i feel like small diamonds kinda get lost on my chubby hands."
"I know real diamonds the size i wanted would be wayyy too expensive so i looked into moissanite & found beautiful rings so i even told him i didn’t want expensive real diamonds i just wanted moissanite in order to get a bigger rock & my style & as long as it didn’t turn my finger green."
There's loads there to go on, but long story short the hubby ended up with a ring she hated that was "opposite of everything i showed him".
So the couple get engaged, and the bride sits on her feelings, afraid of disappointing her partner and hoping to learn to love the ring he had gotten her.
But just a week later, the truth comes out and the other half gets pretty mad.
She asked if she could take the ring back, exchange it and even give any extra money back to him, but he was so offended "saying how ungrateful & spoiled I am & hasn’t even tried to return the ring."
Is it forgivable to get it so wrong when the woman in this story gave him so much to base his decision off?
Or is the bride-to-be being overly dramatic?
Who's being the a**hole here?