“If you don’t care for Joel’s messages, just don’t turn on the program and let God, and not man, sort it out.”
So Christians shouldn’t sound the alarm when sinners are being ushered to eternal destruction by a very public false teacher? I don’t think you can find much biblical support for that notion.
He used the furnace example in a metaphorical sense, not a literal sense. If he made a statement about God’s power and protecting his children always by instead using a miracle that happened in the New Testament era, such as the promse if eternal life through Jesus, and his rising from the dead, would you still be complaining?