Carson is a Seventh-day Adventist, and hence a young-earth creationist. (Yes, I know. It's mind-boggling, isn't it?) And he's stood by the remark. So almost certainly he was being (and continues to be) serious.
I'm not sure if this shows he is really serious or exactly the opposite.
In Poland there is a guy, Janusz Palikot, who in 2005 owned a "Christian", anti-(many things including LGBT) newspaper but later sold it and founded a pro-LGBT, anti-religion political party.
"God has revealed in Scripture the authentic and historical account of His creative activity. He created the universe, and in a recent six-day creation the Lord made “the heavens and the earth, the sea, and all that is in them” and rested on the seventh day."
Yes, they quote the bible. Yes, many Christian churches quote the same text and call it the same. No, it does not mean all Seventh Day Adventists are young earth creationists.
I didn't say all 7DAs were YECs. But the fact of the matter is that YEC is the church's official position. And Ben Carson is on record as believing in a six-day creation, and professing ignorance of the age of the earth. So we can quibble over the YE part, but not the C part. Ben Carson is without question a creationist.
Source for which? For grain in general? For Josef supposedly being the one to store it? Or for the pyramids having nothing to do with the Jews being slaves in Egypt?
For Hollywood. You said that associating pyramids with Biblical events was their idea, so I thought that maybe there was some particular movie which spawned this meme.
I don't think it's created by Hollywood. I don't think it'd be all that odd to assume they might be the legendary grain silos when they'd just been found and hadn't been opened up yet. It's just that after they've been opened and examined, and we know a lot more about them, it's silly to cling to something that's so obviously false.