Is this sentence grammatically correct

What is she throwing an attitude about?


too finicky 7throwing an attitude

I'm not familiar with this expression. It doesn't seem like standard English. Maybe it's fairly new slang. A more standard way of expressing it is

Why is she being so arrogant?


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too finicky 7What is she throwing an attitude about?

"Throwing" is unfamiliar to me. In my day, we "copped" an attitude.

If you want to use throw idomatically, you could say eg What is she throwing a fit about?