There's trace amounts of blood in meat. They drain out a huge majority at the slaughterhouse, but it's nearly impossible to get out every drop. If there's a lot of blood in your meat though, something probably went wrong at the slaughterhouse.
Some cuisines feature actual blood as an ingredient though - blood sausages from the UK contain actual significant amounts of added blood, cubes of solidified pork blood "tofu" are considered a delicacy in some places in China - I think it's safe to say people that enjoy those kinds of foods can be said to eat blood. But I don't think people that eat meat can be said to eat blood, for the same reason that you wouldn't say someone that drinks tap water drinks mercury.
IDK man, even your rocket scientist probably has hobbies and other shit besides rocket science that they like doing but are kinda bad to good at, which leads to a lot more fulfilling of a life than only being really really good at rocket science. Which is the whole point of the comic.