The following article contains spoilers from Robin #13, on sale now.
After witnessing Angel-Breaker murder Doctor Moon in Robin #13 (by Joshua Williamson, Roger Cruz, Norm Rapmund, Luis Guerrero, Troy Peteri) Deathstroke rightly called out Batman's hypocrisy for only wanting to take him in, even when Talia al Ghul is just as guilty of appalling crimes. One of her minions had just murdered a man in front of Batman, yet it seems as though Batman is only concerned with bringing in Deathstroke.
Though he's hardly a saint, Deathstroke is right to call Batman out over his selectiveness when it comes to delivering justice. Talia is just as much a part of this war as Deathstroke is. And considering that both he and Batman believe Deathstroke is innocent of killing Ra's al Ghul, then only Talia is guilty of any immediate wrongdoing.
Batman has had a number of opportunities to arrest Talia since the war started. Adding to this, Talia was injured, preferring to heal naturally instead of using a Lazarus pit. If a fight had broken out between them when Batman attempted to arrest her, it would be a short one. Instead of doing the right thing and taking her in, Batman took the time to romance her.
Now, his feelings for Talia, regardless of his love for Catwoman, are the most obvious reasons for him not trying to arrest her. There could be other reasons though. His son, Damian, for example, might be an important factor. Batman has been trying to reconnect with his lost Robin for some time now, but their latest meeting did not go well because of Batman's inability to connect emotionally with people. Perhaps he thought that arresting the mother of his son would be the deathblow to any chance of fixing their relationship.
If emotional factors weren't enough, then practical ones might have tipped the scale. It's possible Batman suspected that even if he had apprehended Talia and somehow gotten her out of her fortress, that the war would not stop. Her orders would still stand, and she would never rescind them for anything. In addition, her followers would undoubtedly try to free her, adding to the chaos and endangering regular law enforcement. Deathstroke seemed the easier target. And yet, he has an army of villains at his disposal who are loyal, and if Deathstroke had been responsible for the death of Ra's al Ghul, then the war would have been continued by his followers who would also have tried to break him out of prison.
Overall, it is clearly a complex situation. Deathstroke is still correct that Batman's pickiness when it comes to whom he deems a criminal makes more problems than solutions. Many people have died because he didn't arrest Talia sooner. His selective justice will only endanger more people as time passes.