We don't eat chocolate bars with no hechsher. What are we afraid might be in them, whether through the equipment or directly? Let's take the case of a dairy chocolate bar that wouldn't be served in the White House, to avoid bishul akum. And I'm assuming R' Moshe's heter for chalav stam.
In theory, there could be Israeli tevel cocoa beans or idol worship products, but as far as I know the only ones that are actually likely in the US involve products derived from meat.
The problem is that if the meat comes from a kosher animal, when the chocolate is heated to melt it this would become basar bechalav on a Torah level. We would have to avoid benefiting from the chocolate bar, not just eating it. I don't see any reason to expect that products derived from cow are much less likely to be there than products derived from pig, for instance, which wouldn't pose this problem.
Am I wrong, and pig products are much more common than cow products? Or is the reason we need a hechsher for chocolate bars something other than meat? Or do we require a higher standard of knowledge for eating than for benefit?