What does ‘Red meat rhetoric’ exactly mean?

From "Looking for Red Meat Political Terms That Won't Bring a Hail of Dead Cats" (June 12, 2008):

WILLIAM SAFIRE: I was looking for some criticism of people who were defeatist, who thought that we could never win in Vietnam. And so I came up with the nattering nabobs of negativism. That is known as red meat rhetoric. When you talk about 'there is no red meat in this speech,' that means there is no ammunition you can feed your supporters to use or throw into the cage of a lion that was hungry.

So basically he says 'red meat rhetoric' is about making substantial, "nutritious" statements, not beating about the bush or hand-waving with general terms. So it involves a bit of both of your definitions. It can also dip into a populist speech.

The old MSN Encarta defined this term, referring to:

communication forceful and to the point: pithy, forceful, aggressively delivered, and focusing sharply on contentious issues ( informal )

So if Obama (or any politician) is referred to giving red meat rhetoric, then they are delivering forceful and powerful speeches to their audience. This could be analogized to feeding red meat to a bunch of tigers--you're feeding the crowd, getting them riled up.

The term "red meat speech" refers, yes, to "something to chew on;" but the expression may have come from feeding time at the zoo, specifically at the lion cage, where the keepers toss large chunks of fresh red meat to the hungry carnivores while an eager audience of visitors goes into their own feeding frenzy, cheering and screaming as the ferocious cats tear, chew, and digest their favorite meal.

Here's my favorite example of a red meat speech featuring former Michigan Gov. Jennifer Granholm's speech at the 2012 Democratic National Convention. She worked the house beautifully, delivering the message with lots of memorable take-away value, all the while whipping the crowd into a frothy frenzy: https://www.youtube.com/watch?v=g5mw_6s5vh8