So we should not plan/prepare because others are unpredictable and destroy all plans/preparations?
That is the very formula for becoming part of the problem.
We prep so that we can be a part of the solution, at least for our own families and those in our prepping circle.
As far as the unpredictability of others, they can do what they want. If they don’t want to prep and they want to starve when the SHTF, that’s their choice.
If their unpredictability leads them to try to take my supplies and parasite off my prepping (whether from unfriendly looting or friendly looting — those friends and neighbors who laughed in your face for years and said, “well, if anything does happen, I’ll come to your house”) then most of us are prepared to control their ‘unpredictability.’
There is no 'unpredictability' there; they are telling you outright what their intent is should they be faced with adversity.
OPSEC is the primary concept which should be foremost in your mind for your sake, and that of your family; neighbors and community can be provided for as you wish.
Don't forget that envy and greed are basic human characteristics, and that ethics get bent and contorted when it comes to basic survival.
Another concept is cache : storage of supplies in several locations should one supply depot be compromised.
In a "bug out" situation, cache your supplies enroute to your desired end location, strategically placed at comfortable travel intervals.
In a "bug in" situation, cache your supplies in several locations known only to you and your companion, again within a comfortable distance.
If you unable, or unwilling, to protect your home or cache supplies, you don't own them; that is where the sense of community can come together = mutual defense.