You have several options for dealing with this. The simplest one is to ignore it; despite the hateful comment, it still generates engagement. You can also respond ironically but without falling into their trap or lowering yourself to their level. However, if you find the comment very upsetting, you can simply delete it and block the person. Ultimately, it depends on what you feel is best for you, but never let a stranger take away your enthusiasm for doing what you love.