A moment's thought makes it clear how wise that process is. Suppose the Founders had actually provided that all major decisions must be made by "consensus." Would the consensus have to be unanimous? Surely not -- there will always be some crackpot senator or congressman who would refuse to go along. So each party would have to arrive at its own position by whatever method it chose, then seek consensus with the other party (or parties). That is not far from what actually happens in many cases today, but it doesn't provide for situations in which the parties cannot or will not reach a consensus with each other. So a vote simply must be taken, and the will of the majority will prevail.
Actually, experience teaches that the nation is often most ill-served when the two parties do in fact "get together" and agree on something, rather than resolving their differences by a majority vote. There are many examples of this in every session of Congress. If the parties privately agree on (say) what officeholders' salaries ought to be, or what perks they ought to enjoy, you can bet the losers will be the taxpayers. Far better that such things should be slugged out between the parties, with the minority loudly accusing the majority of overreaching.
Yes, the brawls between the Republicans and the Democrats can get tiring, and both are routinely guilty of posturing just to look better than their rival. But that way we at least get to see what's going on. It's when harmony (and silence) reign on Capitol Hill that the voters have most cause to worry.