In the context of political discussions, especially online, the term "idiot" seems to be returning to its original meaning of an uneducated or ignorant person or one who thinks primarily of their own interests (e.g. private profit), as opposed to an educated person who takes an interest in public affairs and is concerned for the common good.
In this context, an accusation that someone is "[being] an idiot" is almost never an accusation of actual mental deficiency -- since mental deficiency would be a perfectly understandable reason for possessing unrealistic or self-centered political views -- but more an accusation of willful ignorance, typically because of adherence to dogma of some kind.
- Conservapedia: hews to the more commonly-accepted, non-debate usage
- Online Etymology "idiota "ordinary person, layman; outsider," in Late Latin "uneducated or ignorant person," from Greek idiotes "layman, person lacking professional skill" (opposed to writer, soldier, skilled workman), literally "private person (as opposed to one taking part in public affairs)," used patronizingly for "ignorant person,"..."