Aikido is one of those arts that just does not come naturally. Punching and kicking comes naturally, so does grabbing someone and trying to push or pull them over and onto the floor. Not that Karate and Judo dont require skill, but you build on something you already have with these arts, with Aikido you start with nothing.
Its a bit like my perception of Shaoling Kung-Fu. How do they manage to move let alone fight from those deep stances. How do you ever get those complicated animal styles to "come naturally" enough to use them in a fight? Very few people I have met doubt the effectivity of Shaolin Kung-fu though, whether they have any proof that its effective or not is a different matter.
What did you want to hear from people who have invested a significant amount of pain, sweat, tears and blood into THEIR martial art anyway? That your martial art is better or more effective than theirs? thats crazy!