Maybe she's wrong but your argument is incomplete, saying something developed alongside language doesn't explain how it evolved or what relationship it has to language. What if both language and morality have a deeper rooted cause / selective pressure? Sure morality and language are intertwined but so are all of human concepts and mechanisms available to our cognition, otherwise we wouldn't be able to talk about it right now or retrospect. That does not mean that mechanism doesn't exist independent of language to some degree. In fact I would argue that language in its current form is only capable of representing morality in an objective way which does not exist in real world, hinting to us a more complex relationship between language and the actual source/reason for morality. See what Wittgenstein wrote on this topic and you will understand what I mean. Bottom line is that either explanation is not very satisfactory to me because both are partially wrong or incomplete, calling it flat out bullshit is trivializing the issue and pretending we have the complete answer.