Trump might be a couple of wrongfully committed patients short of an insane asylum but he does kind of have a point; in context it's patent nonsense he's killed his campaign by his words and deeds but your choice of news outlet can be a an echo chamber where it's easy to propagate certain ideas and norms, trump supporters are surely a case in point.
I think it's incredibly difficult to rig an election, sway one sure but the level of complicity in rigging an election would be immense. We have a postal voting system here that's ripe for exploitation; the number of postal votes recorded for some areas during our independence referendum for example seemed suspiciously high for some areas but I'd fall short of saying it was rigged.