That's precisely the mentality. They have a gun culture; we don't.
If you accept the premise that the bad guys can access guns no matter what laws we pass, then why should we prohibit law abiding citizens from bearing arms? (btw, the logic seems sound to me; guns are used to perpetrate crimes, so why would a law deter someone who is inclined to violate laws in the first instance?)
According to the FBI, the average active shooter incident lasts 12.5 minutes. Active shooter durations with armed bystanders is something like 3 minutes. Some cowboys like to to cite that statistics to support their argument for concealed carry. (But, most sane experts will tell you NOT to engage an active shooter - because the shooter will then engage YOU and you greatly increase the risk of friendly fire).
As for whether the baddies are better shots, etc. Maybe, maybe not. Training with your weapon is a must for those who choose to carry. I don't know if bad guys spend time at the range, but sending lead downrange on the regular is part of gun culture.