You're not right about Hume. Hume thought that Emotivism was the patch-up for the Guillotine. However, I don't think there's any serious philosopher who believes Emotivism anymore. It's just another set of ungrounded substantive claims. I has no durability in the face of skepticism.You misunderstand Hume. His morals, like Schopenhauers were based on compassion, or as Hume I think said, sentiment. Remember, Hume also argued that you couldn't prove any causality, that didn't stop Hume believing in it nor did it stop him being an ethical man. He couldn't prove is to ought, he didn't care either.
Hume "cared."
And Hume did think he'd "solved" the Guillotine by Emotivism. But he was simply rejoicing too soon. Subsequent moral theorists have torn his assumptions to shreds. Some of them (like Searle) still hope for a solution to the Guillotine; but everyone pretty much agrees that Hume didn't have one. As of this moment, the Guillotine stands, and is a major problem in modern moral theory.
Now, whether Hume was an ethical man or not is not on topic: he may have been quite nice as a person, but we know he did not discover any rational warrant for a claim that such behavior was necessary. He could also have chosen to be a rotter, as, I understand, was Shopenhauer, despite his elaborate theorizing on compassion. Good people can have a bad moral theory, just as bad people can have a good one that they simply choose to ignore in practice. Not personal conduct, but rational warrant is the issue here.
Ad hominem: definition: arguing against a person when you should be arguing against the logic of his statements. It's a fallacy because even honest men occasionally make mistakes and inadvertently "lie," and inveterate liars spend much of their time telling truths or partial truths. It's the statement, not the man that decides which it is.