Anyone who has studied the history of the past 1000 years or so, has seen countless people branded as the AntiChrist. Someone interpreted a Nostradamus verse to identify Napoleon as the AntiChrist. Of course, Napoleon was long dead at this time, so the information was more trivial than useful. Hitler was another candidate for AntiChrist and would seem better qualified than a man who in hindsight was just an annoying Frenchman.
Then, as now, calling someone the AntiChrist is just a rhetorical flourish, which has no more meaning than, "I really don't like this guy."