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In isolation you can find many examples of this. But, political alliances mean that group may be trading financial support for support of another issue. Farm subsidies and net neutrality could be traded with people voting for both even if they only care for one or the other.
It smells like corruption, but political horse trading does represent people caring more or less about different issues.
Consider three friends going out, one cares a lot about the movie they watch, another cares about what they eat for dinner, and the third really wants to go out to a specific club afterwards. If everyone votes on each activity separately then people may be less happy than a compromise.