It wasn't just seen in the book but in the film as well. Pretty much all of the Slytherin's were rooting for Krum during the Triwizard Tournament. Even toward the end of the book/film they were cheering for him during the third task. (In the movie you see Malfoy, Crabbe and Goyle shouting for him to win, and Crabbe had the name Krum painted on his forehead). And here we have many Slytherin's especially Malfoy who are known to hate muggleborns, and yet Krum is partially dating Hermione. It was an EXTREMELY obvious fact that he took Hermione to the Yule Ball and hanging around her for a lot of the book/film. But still, Malfoy and the other Slytherin's continue to fanboy/fangirl for him.
Doesn't anyone else find it both odd and funny that they loved him so much and yet they had to have known he was the date of Hermione, a known "mudblood". You'd think they would have started to hate him or think of him as a "traitor" ....... but they didn't.
"Their flesh shall nourish yours, their blood shall flow within you, as the beetle nourishes the lark so shall human nourish vampire."