Usually the AI will avoid taking any action that will certainly and directly result in death, such as trading a minion into an Abomination when they have 2 or less health, even if it means passing for several turns while the opponent is showing lethal. The Horseman should know that losing its head is as bad as losing its own hero, and refrain from attacking suicidally.
https://hsreplay.net/replay/mp78Sj6z62Q8dubkdWo2fC#turn=17a
Usually the AI will avoid taking any action that will certainly and directly result in death, such as trading a minion into an Abomination when they have 2 or less health, even if it means passing for several turns while the opponent is showing lethal. The Horseman should know that losing its head is as bad as losing its own hero, and refrain from attacking suicidally.