Reductio ad Hitlerum, a fallacious argument. Hitler was a vegetarian, therefore vegetarians are fascists.
Hitler was a vegetarian, therefore vegetarians are fascists is an invalid argument (notwithstanding the facts), but it is the fallacy of affirming the consequent. And what should we call the fallacy that any argument that contains the string 'hitler' is thereby invalid?
Your claim "that complaining about a free and fair election and trying to overthrow the legitimate government with armed force" is given the lie by the observation that Hitler --and more pertinently Mussolini --came to power in free and fair elections and headed the legitimate governments of their country until they were overthrown by force. It is neither the fact of being democratically elected (or not), nor the fact of being overthrown by force (successfully or not), which defines 'fascism.' Stop digging deeper!
Note, I'm not arguing that Erdogan is literally a fascist (strictly speaking he is not); But his behaviour, especially post-coup, sure make him look a lot more like a fascist than the men with "uniforms, tanks [&] guns," who landed on Omaha Beach with the aim of overthrowing the government of Germany. (Or the mutinous faction of the Turkish army for that matter.)