Nah, it was Harry getting briefly involved with one of the Paki sisters. Fortunately, he smartened up later.

So far in the game, the only mention of "purebloods" had to do with a mention of someone with the surname Gaunt, which would be one of Tom Riddle's direct ancestors, anyway. At the time, it should have been considered nothing more than a mere personal choice as to whom one married; I seem to recall the books laying the whole pureblood thing directly on Voldemort's shoulders (as being a shit-raiser.) At worst, it would have been looked at in a more tribalist sense before Darwin, in the same sense that royal families made the mistake of wanting to keep things to the nearest family possible, or the multi-generational cousin-marriage we see in modern tribalist societies (which would make sense given that they're all literally inter-related, with maybe very little fresh blood, such as the Grangers.)