In the same way it's in the interests of shop-owners to continue a good relationship with the mafia. During the cold war, if an "ally" didn't have a good relationship, they could see their government undermined, pressured in all kinds of ways, or even toppled with their support. Not much different today, though it's less in the open.

"Allied" can mean a lot of things, but it can also be forced upon populations, have them dragged into wars for your side's interests, and so on. Not everything is what it writes on the tin.