Arjuna completes his thought from the previous verse. He asks Krishna: O Janardana, when we can clearly see the wrong that comes from destroying a family, why should we not have the wisdom to turn away from this sin?
His argument is straightforward. The Kauravas are blinded by greed — they cannot see what they are doing. But we, the Pandavas, can see it plainly. The destruction of the kula, the betrayal of friends, the sin that follows — all of it is visible to us. And if we can see the pit in the road, we are obligated to avoid it. Walking into it knowingly would be an even greater wrong.
There is a quiet moral confidence in Arjuna's words here. He believes that awareness of consequences creates responsibility. Committing a sin while knowing it is a sin — that, to Arjuna, is the worst kind of wrongdoing.