Some people may eat brats pink, but others may be against it. Brats are typically made from pork. They are sold in stores raw, meaning unlike hotdogs, they are not ready to eat, just needing to be warmed up. Instead, these brats need to be cooked to be safe to eat.
The rules around the cooking of meat vary between the types of meat. The United States Department for Agriculture (USDA) has some very strict rules about cooking meats, especially when it comes to ensuring they are cooked safely and adequately.
Chicken, and other poultry, for example, cannot have any pinkness. Beef, on the other hand, may be fine with pink and even red (hence the love of rare steaks).
Pork sausages such as bratwurst are recommended to be cooked to at least 160 degrees Fahrenheit (this is an internal temperature recommendation), and so provided they are this temperature they will be safe to eat, whether they are a little pink or not.
Rely on an accurate food thermometer rather than the color of your brats to know for sure if they are safe to eat!