With freedom of speech and expression must also come restraint out of respect for others and societal norms, including the norms of the moderators and members of UU. It was the choice of a moderator to close the previous thread. I am sure that the moderator did so to avoid a pissing match among UU members. That's a pretty standard way for a moderator to keep a forum's focus on topic.
A poet/lyricist must write what he must, often outside the bounds of conscience. But if the result is a work of derogatory intent, expect to receive some pushback. I have written a fair bit of poetry in my life, some of which I would not share with my wife or my parents or the folks on UU.