It means there are people out there who believe they can win arguments by creating false analogies to Hitler, who is basically indefensible. Godwin's law then makes it really easy to identify trolls, and you can avoid feeding them by not taking the bait.
Godwin's Law doesn't state that as soon as the Nazis are mentioned, that the quality of the conversation is zero.
There is a difference when drawing a comparison about something entirely unrelated, but when you're talking about topics involving wiping out a people, claiming Godwin's law is silly.
Hitler wiped out a huge number of people. That's the topic of this comment thread. Therefore, bringing up Hitler is totally fine because it is directly relevant.