Words have no inherent meaning. They mean only what they are understood to mean.Of course the intention of words and language is to communicate, so words ought to aid that endeavor. Commonly used and unambiguous words do that. Words that no one can agree what they mean do exactly the opposite. Which is why I partially agree, and partially disagree with this.
I agree with their usage of ambivalent. There's no other word that closely matches it, and if you want to say indifferent, you can say indifferent (or apathetic).
As far as literally goes, I've never seen it used it to mean figuratively. Never. It's used as an intensifier. Frequently used in the same way as really. But never figuratively. At best, it's used in a figurative sense, but that's not the same as saying it's used in the place of figuratively. That would mean you could replace the one word with the other, and the phrase would mean the same thing. That doesn't work. Though I do think, for the sake of clarity, that literally should retain its literal meaning, rather than being used as an intensifier.
Funnily enough, enormous used to also mean wicked. You don't see anyone complaining about people misusing that anymore...
And by my authority as a blogger, I officially remove the word nonplussed from the English language. No one knows what the word means. Even if they do, they don't know that people they're communicating with understand it the same way they do. It fails to communicate clearly, and should not be used. Besides, look at it - nonplussed. Clearly neither definition given is correct: It means subtracted.