It makes sense when you think about it. How many times have we heard the rationale for Trump: I Just want someone to blow up the system. Well, the same can be said for Sanders. If you don‘t care precisely how the system is to be blown up, then you can support either one.
Theoretically, this is why most of us have an ideology to begin with. It allows us to discern the authentic man from the charlatan. Unfortunately, most Americans do not have a political ideology except that imbued by pop culture.