No, I'm sorry, not all old people are racist or magically 'excused' from being polite just because they're old.
My mum's side of the family are INCREDIBLY White/English, my nan was a Hunt before she married my grampa, a Smith. A bit further back you get some French's but I daresay it was some time ago they came over to England from the continent to end up with that as a surname!
Anyway. It was a fairly racist society back then, my nan used to work with a black man, I can't remember where - either a shop or the local bio lab (I forget). They became friends and brought him home to tea once, much to the consternation of her own mother who I don't think liked that very much...
Point being if you're a closed-minded grumpy git, I suppose you're likely to be racist too. Goes for all ages. But if you're open and friendly and lack prejudice, then you won't.