It is racist in a way. There is no country in which everyone eats cats or dogs. There are also probably not many countries where not a single person has ever eaten a cat or a dog.

“People from China eat cats and dogs” is no more true than “People from the US eat cats and dogs” Sure, the amount of people in China that have eaten cat or dog meat is likely higher than the corresponding amount in the US, but that’s not what these statements mean.

If someone says “People from China eat cats and dogs”, they are very likely to have some racist intent.