First off, I can't recall a time Himaruya drew Antonio with a bull. If it has something to do with the fanworks, though, then I hear you.
You can't deny that one of the things Spain is famous for is it's bullfights and matadors. Therefore, a lot of fanworks depicting Antonio as a matador would be common. It's the same deal with tomatoes, olives, wine, guitars, fiestas, flamencos, sangria, castanets, going out in the world and being an awesome empire... you get the picture.
That doesn't mean, however that the rest of the great things about Spain aren't remembered by the fans. People just don't usually draw/write about Antonio with these things because a) Not everyone knows about these things, b) It doesn't usually bring up the image of Spain to mind, and c) It's difficult to depict. Usually when the opportunity comes, though, these things are referenced or are even an element in fanfiction. And usually, there's some historical basis to it.
It's the same deal with Russia, unfortunately. It's easy to associate vodka with Russia, and it's a very common stereotype too. But stereotypes aren't meant to depict every single person in a certain country- they usually just show a general representation of what's common there, or what they're best-known for. It's common knowledge that not everyone can be associated with a stereotype.