A conspiracy theory is an explanation for an event or situation that invokes a conspiracy by sinister and powerful groups, often political in motivation,when other explanations are more probable.
That probable part is key. Something can seem improbable if your assumptions are wrong.
It's unfortunate but a lot of right wing stuff at this point is conspiracy theory. In my more paranoid moments it feels like part of a strategy. If you only imply things, and don't make direct accusations you can't be refuted.