Why would the Antichrist offer a hog on the temple altar?
The Antichrist would offer a hog on the temple altar out of orneriness and demonism, to defile the temple. Since a hog is anathema to a Jew, slaughtering it and spilling its blood on the altar would be a deliberate desecration, after which he immediately turns on the Jew.
Les explains that because the Jews will be back into animal sacrifices and the altar will be operating, the Antichrist will probably, out of orneriness and demonism, offer a hog. That act is anathema to a Jew—the very thought of a hog being slaughtered and its blood spilled on their altar is detestable. Les says that whatever he does, he will defile the temple and then immediately turn on the Jew. Jesus identifies this event as what Daniel was talking about, and it triggers the instruction for those in Judea to flee to the mountains.