Yeah but you don't just get to decide what words mean to suit your argument. The Spanish civil war and Syria are perfect examples of something that is widely considered a civil war and were multilateral.
Most civil wars start as multilateral conflicts. But once groups start getting picked off, the others begin combining into larger structure to preserve themselves and increase their chances of having a stake in victory. Just because you can't see the lines now does not mean they can't emerge after the conflict begins.
I do think the point about age is relevant. It's well know that things like crime decrease significantly with age. We also don't have much historical precedent for the kind of aged populations post industrial countries have.
Most civil wars start as multilateral conflicts. But once groups start getting picked off, the others begin combining into larger structure to preserve themselves and increase their chances of having a stake in victory. Just because you can't see the lines now does not mean they can't emerge after the conflict begins.
I do think the point about age is relevant. It's well know that things like crime decrease significantly with age. We also don't have much historical precedent for the kind of aged populations post industrial countries have.