I have not said that people do not have the right to defend themselves. I do not have the authority to say such a thing.
Let’s do a thought experiment: so people have a right to defend themselves. Does that mean we are allowed to have machine guns? What about drones with a weapon payload? What about killing somebody before we even know their intentions?
So a generic “right to defense” does not translate to a right to own a particular piece of hardware. It simply means the Church recognizes a person’s right to self-preservation. If that meant there was also a God-given right to specifically own X, Y, or Z firearm, then the Holy See would have spoken about the issue with authority, in the way it has on other subjects, such as abortion. The Church isn’t afraid to officially teach things that are contrary to popular opinion.
So people’s opinions towards guns are just that: an opinion.
The 18th century Enlightenment thinkers who wrote the US constitution called it an inalienable right. By the 16th century it was fashionable for intellectuals to speak on God’s behalf. But saying it doesn’t make it true. And lawmakers & judges can go to great lengths to interpret it.