It could be a downright hatred of these games/game series, or in my case, it could just be that you don't really like it yourself but you could understand why other people do.
My Personal Examples:
Pokemon: I can completely understand why people like these games, I just don't. One of the things I don't like is that the games are too "happy" if you know what I mean. Everyone's so damn happy all the time and everything's always perfect aside from a few teams who occasionally steal Pokemon. Call me a hypocrite since I like Mario and Kirby, but there's something about Pokemon's perfect world that I don't like. Also, I don't like the battle system. The mostly static battle screens where you just select an attack and watch stuff happen just isn't for me. This actually rules out most turn-based RPGs for me though, so it's not just Pokemon. It's boring to me and I don't like grinding for levels which Pokemon has you do. Also, I don't like the fact that there's no real goal. I've never gotten very far in a Pokemon game or even ever completed one for these reasons.
Earthbound: Earthbound is the only one out of the three I've actually played (which is true for lots of people), and I can see why people enjoy it, it's just not for me. Lots of people like it for its weird, unique style. To me, the game isn't good weird, it's just weird weird. Not my taste. The art-style bugs me for some reason too. Something about the sprites just visually bothers me. Also, just like Pokemon, don't like the combat system. Earthbound's is even more dull to me because you can't see shit. You just have to guess what's happening.
Pikmin:
I actually want to like these games, but they're too stressful for me. I play games to relax, not get more tense. You have so many responsibilities to balance in these games all at the same time (sort of like real life, heehee) and when it all comes crashing down it gets stressful as hell. The fact that the Pikmin are so damn cute and lovable makes it that much worse when you just watch all of them die right in front of you while you can do nothing. It's more my emotional fiber that's the problem in this case than the game itself.