If you were on trial for murder, would you want your lawyer to put aside his differences with the prosecution and, in the spirit of bipartisanship, strike a compromise? Sure, lawyers on both sides should be polite and obey the rules as officers of the court. But we understand that there are some things more important than the spirit of compromise in a system designed to be adversarial.
American politics is adversarial by design too. Partisanship and ambition are the vehicles by which important arguments are made.
Take judicial confirmation battles. Republicans and Democrats alike have been grossly hypocritical or inconsistent on judges. Depending on whose party is running the show, the arguments about how judges should be confirmed has gone back and forth like a windshield wiper. When the GOP was out of power, Republicans pounded the table about their responsibility to study the records of the nominees, while the Democrats insisted the president deserved deference. Flip things around and - boom - the Republicans want deference and the Dems bust out the Federalist Papers.
When you hear people say, "We need to get past partisan differences," what they are really saying is you should shut up and agree with me. Similarly, when public health experts, child advocates, televangelists, environmentalists and the rest insist that this or that isn't a political issue, it's a health issue, child-safety issue, moral issue or whatever-kind-of-issue, what they are really saying is that we shouldn't have a political argument about my cause. Because my cause is beyond politics. You should just agree with me and do it my way.
But even when people make this argument in all sincerity, they miss the point. Virtually all issues are political issues the moment we ask politicians to deal with them.
Politics is about choosing between competing public goods or competing public harms, and expecting politicians to hold hands like the Whos of Whoville and sing in a circle is to ask them to stop being politicians.
So, yeah, peace on Earth and goodwill to all men is nice. But we shouldn't let that get in the way of a good argument.