The Republicans have a 47 seat majority in the House, a 2 seat majority in the Senate, and the White House. Why is this Chuck and Nancy's shutdown and not Mitch and Paul's?
I’m not sure if you are simply being contrary or if the question is serious, but here is my answer:
Chuck and Nancy are the ones coming to the table with “iron clad” demands that have nothing to do with the continuity of government function. More accurately, they are refusing to come to the table unless their demands are capitulated to before negotiations start.
Assuming that the republicans can hold together every single vote, the Senate still cannot overcome a democrat filibuster under the current rules. While I do not believe that the rules should remain as they are, the reality is that Chuck and Nancy are the ones playing chicken with the process - so they are the ones who should be “credited” with the obstruction they espouse.
60 votes in the senate. This is not complicated, really.