just

It's not usually the case that entities do things just because of one impetus or motivation, to speak colloquially.

More technically I'm not sure how much logical sense it makes to ever say that something is just because of something else. When one speaks like that, one invites the listener to agree to hold a basically infinite list of factors constant, and the claim is that nothing not on the list, if changed, would cause a change in outcome. This can lead to confusion because it's hard to specify the list, so it's often better to directly claim that a certain thing is not a cause, and try to enumerate such things.

To give a silly example, why was the Roman army defeated at Cannae? Because they were encircled...yet if they had been armed with loaded AK-47s and trained in their use, encirclement would not have mattered. Obviously, when discussing Cannae, we implicitly agree not to counterfactually consider if they had twentieth century firearms. But there are also borderline cases for which it's not obvious whether or not something belongs on the list. Why was the Roman army defeated at Cannae? Because they didn't have enough men. Some greater number of typical Roman levies would have allowed them to win there, or dissuaded Hannibal from engaging them. This seems probably illegitimate to say (to me, at least), yet it seems legitimate to say of the Spartans at Thermopylae that they were defeated because they didn't have enough men.

I disfavor the construction "just because" and the like because so much in it relies on aligned intuitions.