I don't think you are being irresponsible.
Does he stay in a crate while you are away or does he have the run of the house. We take our dogs to work with us. Barking is still a problem because my business neighbor doesnt like it and I don't blame him! But I keep a water bottle handy and he knows he "gets it" when he doesn't stop. He's allowed to alert us, but then he must stop.
When they are at home and we go out, Angel stays in his crate/carrier, Susie our golden, has free run, but we turn the television on and draw the curtains closed. 95% of the time, if they cannot see or hear anything outside the house, they will not bark. They do bark when we come home sometimes.
Barking is a tough one to break, I think. Because unless you're there to correct it its difficult. How old is he? He will probably settle down when he gets a little older.