Is it responsible to have your gun with a round in the chamber and the safety off if you aren’t getting ready to fire at a target?
Absolutely.
Many, many handguns have no safety; by which I mean that the gun will fire if there is a round in the chamber and the trigger is pulled. The "safety" is to not pull the trigger.
Also, most handguns require two hands and an additional second or so to chamber a round. This could make all the difference in a life or death situation. When faced with danger, the adrenaline surge will reduce motor skills considerably. Minimizing the actions needed to stop an attack is vital.
If everyone follows the four gun handling safety rules, it becomes very difficult for someone to be injured.
1) Treat every weapon as if it is loaded.
2) Don't point the gun at anything you are not willing to destroy.
3) Don't touch the trigger until you are ready to fire.
4) Be aware of your target and what is beyond it.
Obey the rules and stay safe.
Most of my semi-autos have no safety to have off, and I ain’t carrying a gun with no round in the chamber. The secret is don’t play with a loaded gun and don’t pull the trigger unless you’re ready to shoot.