I've never gotten the satanic thing from non-gamers, but there is no denying the "Nerd Stigma" that D&D holds. Furthermore, I have experienced a couple instances recently when people spoke pejoratively about D&D without knowing I was into it. Just a couple days ago I was on a baseball forum having a disagreement with someone who said to another poster that I "was probably posting between games of Dungeons and Dragons." Jeez, I wish

I tried to press him about why that was an insult, but he wouldn't offer anything.
The other time was in a philosophical/psychological debate when someone said to me "This isn't Dungeons and Dragons" in reference to something having to do with the ontological status of supposed non-physical sentient beings (i.e. whether or not angels and demons were real beyond human psychology); they were in effect saying that my opinion was not based in reality but fantasy. What I
should have said, but didn't, was "No, this is Mazes and Monsters, and I'm off to kill the dragon that lives in the tunnels below the city."
On a more serious note, I have noticed myself getting a bit defensive on occasion about my gaming interest, sometimes feeling the need to justify it as more than just a "nerdy past-time" by saying that it is highly creative and imaginative, kind of like Poker Night for People with Imaginations. My wife, who is not a gamer, has wondered why I am defensive about it and I have tried to explain the social stigma, but she seemed dubious. She just hasn't experienced it from the perspective of either the "hated" or the "haters."
Finally, I will play Devil's Advocate for a moment and say that many of the gamer stereotypes are based in some degree of reality. There
are quite a few "unhealthy looking" gamers out there, whether obese or malnourished, unhygienic or lacking social grace. Not the majority, but I would say a higher percentage of gamers--or at least patrons of game stores--fit some of these characterizations than, say, coffeeshop hipsters or fashionistas. While I like to look at individuals on a case-by-case basis without culturally stereotyping them off the bat, I don't think there is anything wrong with observing trends.