On your points about believing that training should be required before someone is permitted to carry a firearm, and the fact that you know some people who should not be allowed to carry, just reaffirms why we should NOT have to do anything to utilize our right to keep and bear arms. What training do you think is sufficient? And more importantly, what training might someone who hates guns, hates gun owners and is terrified of guns thinks is appropriate? Once you agree that someone, whoever that someone is, should make that determination, you open the door for endless problems. Just like the states that have "may issue" instead of "shall issue" concealed carry laws. When some local or state politician gets to determine who really "needs" to carry a firearm, you can be sure that average Joe citizen is not going to get that approval.
And just as you think there are folks who should not be allowed to own, let alone carry a gun, you can be sure that there are lots of folks who would put you in that category. Some people think that anyone who wants to carry, by definition is unsuitable to carry.
Unfortunately we live in a reality where training, licensing, etc. are required, so the best we might achieve is to make those requirements as simple, clear and benign as possible to avoid the likelihood that those type rules will be used to stop us from carrying, rather than just trying to make it safer. When pro-gun folks start to agree with our opponents that we need "reasonable" restrictions on guns and gun owners, beware of what will follow next.
And as to the deer/car collisions. Why not put the deer crossing signs in open areas so that drivers will see the deer clearly when they come to that spot to cross the road?