Sometimes the choice you have is between two bad options. Neither option is particularly desirable but a choice has to be made nonethless. I am afraid this is the position Chuck Schumer was in when he decided to go forward with the Continuing Budget Resolution. One option is to shut down the government, which is what many Republicans want in the first place, or continuing funding a government which Trump and company are trying to dismantle.
Fighting the funding seems like a losing battle with possibly worse results than just continuing with the present chaos. What exactly Alexandria Ocasio-Cortez expected Schumer to do is unclear. Fighting for a better bill, particularly when large segments of the Republican party would love to shut down government permanently, seems like a losing battle with the stakes being even greater chaos than we are presently experiencing. Primary him if you must but Schumer is making much more sense to me than Ocasio-Cortez.