It has nothing to do with whether they are realistic or not. I am not a fan of BIG boobs, in real life and in AVNs. I prefer small to medium. That's just my taste. And I like both slim women and thicc women and everything in between.
I used to think I didn't like Big Boobs as well expect the rare occasion but im not so sure anymore. While they usually aren't my preference, every once in awhile I will see some big ones I like. I think it comes down to how the girl looks overall with the big boobs and not just their breast size if I like it , basically if I feel like it works for their overall body appearance / looks or not. However id probably would still will pick the girl with smaller ones most of the time.
I kind of feel the same about asses as well I used to say im an assman but I wouldn't say that as well anymore. I kind of switched to having a preference to liking both equally. As I just value how the girl / LI looks overall more nowdays than one specific feature of. Tho id be lying if I say that is true 100% of the time cause sometimes I will love one thing about an appearance , like when a girl has freckles across their whole body and not just the face. I'd say it's just true most of the time for me.