An honest criticism of modalism?
What criticism makes this a farce exactly, and why can't the same criticism be levelled at Trinitarians? Modalists can believe that God became a man (while also remaining God) and that the man died (although God didn't) and was brought back to life. This is effectively what many Trinitarians also believe, which just goes to show that they are modalists at heart. The farcical parts are that God would become a man (Numbers 23:19, Hosea 11:9) and that Jesus the person, the Son of God, didn't die, only His human nature died.
Lexham Survey of Theology
Likewise, if modalism is true and there is no distinction among the divine persons, then the Son’s humanity and subsequent death and resurrection are a farce, leaving us in our sins.