We can never be sure about people's intentions, but we do see and feel their reactions without a filter on. Regardless, it is a really bad idea to give such a comment so much power over you that it prevents you from taking action.
As a few others have already said, I agree with just blocking the user and delete the comments to secure a peaceful environment for the rest of your readers.
(I tend to give softer advice, but in truth, I would personally just kick the shit out of that person haha~)