In a world saturated in nuance, why do people cling so desperately to a two-party system?

Once upon a time, both sides referred to each other as the loyal opposition. Now it’s personal, not policy differences. As for why two major parties, due to citizen choices and eliminate fringe parties.

deleted by me

I see a variety of "reasons" posted here, but they don't face the reality of the situation. How do we decide when a bill is put on the floor for a vote? Answer that and you will see why we have parties. It is decided by the Speaker of the House. And, how do we chose the Speaker? It is, and always has been, along party lines. At least for the last 100 or so Congresses. Can we change that? Perhaps. But, that would take what? Action by Congress. And who determines what Congress considers? I repeat myself.