Say, for example, that you are considering whether or not to send troops into a foreign country to overthrow a brutal, dictatorial regime.
Some of the contributors may argue that:
(A) Military action should proceed on humanitarian grounds – for example, to bring an end to the violence being committed by the regime against its citizens.
Other contributors may argue that:
(B) Military action shouldn't proceed on humanitarian grounds – for example, as many people are likely to be killed during the invasion and overthrow of the dictator.
In such cases, the ArgumentGroup type lets you bracket all of the humanitarian considerations together [(A) and (B) in this example], and signal via the two-way pro/con rating of the ArgumentGroup whether, when all of the salient considerations are taking into account, you (or the community) conclude that the humanitarian case supports or opposes the military intervention.