Hey everyone- it's important to realize that the reason that "do you eat pig" is wrong is that in English, it isn't really "correct" to say "do you eat pig?"; that's not something a native speaker would ever say. "Do you eat pork" is the most natural-sounding way to say this in English.
Not necessarily. It is also because when most people think of pigs they think of them as pigs covered in mud and other things. It doesn't help that pigs will eat anything.
It's a multi-faceted word. It can be used to shame someone for an umpleasant behaviour or smell. Or it could be used to refer to pigs and its flesh.
It all depends on context tho. Just my two cents. I like to think about words a lot. :P
In spanish where i live, we tend to use "puerco" to call someone who is being unsanitary and unpleasant as well as to refer to the animal.