Both parties care, but one side wants government to do less or not interfere with things, and the other side wants government to do more or redistribute things.

Both parties care, but one side wants government to do less or not interfere with things, and the other side wants government to do more or redistribute things. One side has an interest in government functioning properly and the other doesn't (until they need Medicare anyway). I think this contributes to the "win at any cost" appearance of the one side.