What is the ruling on publishing songs on Instagram with the caption "I disavow your sins" in the description?

Your indication of evil and placing it on websites brings upon you the sin of everyone who commits it, for Allah the Almighty said: "And they will surely carry their [own] burdens and other burdens along with their burdens." These misguided individuals carry their burdens in full and some of the burdens of those whom they led astray. This does not contradict the verses that state, "And no bearer of burdens will bear the burden of another," because they bore the burden of their own misguidance and the burden of leading others astray. This sin will accompany you until you repent. Part of your repentance is to remove the evil things you have placed, if you are able. If you are unable, then sincere repentance is sufficient for you.