When Shelley said poets were the "unacknowledged legislators of the world", he used the term "legislator" in a special sense. Not as someone who "makes laws" but as someone who is a "representative" of the people. In this sense poets, or creators more generally, must be thought of as the voice of the people; as a critical foundation of our society and of our democracy. They offer insights into our world and provide potential solutions - they underpin our future. An attack on creators is therefore an attack on the very essence of humanity.
In the Mask of Anarchy, Shelley presents the tyrannical government of England as very clearly shown as being propped up by bishops and priests. Indeed, Shelley once characterized religion as the "hand maiden of tyranny". He said this because religion is faith-based and encourages people to discard their skepticism and accept things as they are. This is why the recent mania for "stoicism" is so popular in the alt-right movement. It is probably the LAST ancient philosophy we need to revive today. A point that has been eloquently made by Oxford philosopher Sandy Grant. As tyrants threaten to take the stage around the world, we need to keep a close eye on how religion is being used as a tool to control the people. This is why I think my article from last June on some then topical shenanigans of Pope Francis are apropos at this point in time. Enjoy.