The Blues is one of those reminders of how sorrow, rage, even grief, can be joyful in a way when it comes to expression: if not exactly by release, then at least by re-creation.
I like that word best in describing why I speak poetry: despite the usual degree of real or assumed vanity you find amongst those who like performing, I am not so vain as to convince myself I actually create anything. I just work with what is already in creation.
But, I am happy to re-create! Because, recreation is purely about having a good time, it has no other end. Even if my good time is expressing my thoughts on an injustice, addressing social issues, what have you: it is for the love of doing so, the same way the best advocate of any issue is probably the one who would do it pro bono because no money can match the sense of accomplishment and satisfaction they get from speaking and acting on something close to their heart.