That's not so ridiculous, actually. She may have simply objected to his use of the word as normalizing it. Ex. if I call my computer a "fag," I'm not automatically in the right just because it's a computer, & therefore cannot have a sexual orientation to mock.
Although, she is definitely a bit mentally impaired for assuming that "slow" was being used to refer to "stupid," & not actual speed.
Also, you guys have made me ponder where we draw the line between real emotions & fake ones.