Individuals resort to such agreements in the presence of threats, loss, danger or confusion.
Amos

Amos, are beliefs (religious or otherwise), superstitions, and
mis-information part of the category you gave as "confusion"?

If not, I'd like to add those three reasons why people enter into agreements to form groups.

And I think that force of habit and inertia are two additional categories.

Sometimes people won't budge from old habits unless they are pushed to do so-even if the change is in their best interest in the short term and/or in the long term.