How the heck would I know, the man is dead. Far be it for me to second guess him. Maybe for protection from rabid rabbits? No wait that is what Jimmah Carter said canoe paddles were for.
Then stop quoting him telling us about "the strongest reason" as support for your statement that there is only one reason.
When a person tells you what he thinks is the strongest reason, it in no way indicates that there is only one reason. You have no justification from Jefferson for your statement that "the right to bear arms has NOTHING to do with the wilderness or wild animals."
Nothing Jefferson has said suggests that self-defense is not included in "the right of the people to keep and bear arms".