Yes, you're right: It's much better to be unprepared.
It's better to go thirsty, or even watch your loved ones slowly die of dehydration (or dysentery after drinking contaminated water) than to store potable drinking water.
And in the event of an "opportunistic" invasion, your chances of survival are much better if you have no plan, no buddy network, no shelter, no weapons cache, and no supplies.
Some believe Christians shouldn’t store up any wealth. Taken to the extreme, that would mean no food or even shelter. That would certainly make one dependent on God for their daily bread, but is it scriptural?
I don’t believe so. I think scripture teaches us to put God first, keeping in mind that there is no real security in silver, gold, or even ammo (sorry gun lovers). All of it could disappear in an instant despite one’s best laid plans.
Make peace with the Lord first, then be a faithful steward with what you have, being both thankful for it and generous with it to those in need. It makes little sense to prep for everything including a zombie apocalypse while forgetting to prepare for the ultimate test.