- Okay, the MC wants revenge. What I want is for the revenge not to involve the MC "reconquering" the girl who married his enemy. Let the MC get revenge on him, and then let her go her own way without becoming part of the MC's harem.
- In a harem game, all that strategy can do is piss off the players. In a harem game, the ultimate goal is for the MC to acquire a harem (beyond revenge, the harem is what truly matters in the end). Sending one of the LIs to the enemy is like shooting yourself in the foot. You might get a little closer to the goal of revenge, but you're destroying the harem, and at the end of the day, we can live with a less-than-perfect revenge, but we're not going to forgive ruining the harem.
- The villain has already won, twice over. The first time was by stealing the MC's love, and the second time was when the MC sent to him one of his LIs. In fact, this second act makes any further revenge seem pointless. If revenge requires resorting to such tactics, then revenge is no longer worthwhile. However much the MC might try to avenge, he has already lost completely by sending the LI; he can't even hope for a draw.