Introspective Evidence against Emotivism I think you may have misrepresented what Emotivism is about.
It is generally regarded (as far as I know?) as about personal expression; rather than ‘true statements’ it is ‘true expressions’. So if you express that your mother being killed is worse than someone else being killed that is your ‘true expression’ rather than some kind of ‘one size fits all’ statement.
Emotivism is not a ‘belief’ it is a metaethical category which can be use to explore the moral landscape. By saying something we often express opinions about what we believe to be morally right or wrong, but that this is not identical to some underlying/absolute ‘right’/‘wrong’ dichotomy.
Most, if not all, areas of meta ethics serve to question how emotional/ethical/moral terms are played out in academic parse and day-to-day ramblings, as well as the kind of functions and possible miscommunications that can occur alongside these points (including how you or others interpret certain topics of meta ethics.
The general field of meta ethics is - I strongly believe - a hard shift away from parcelling up black and white views we hold dear in order to clear the field of thought for a more generalised understanding of ourselves, others and how differing views and opinions collide.