I think people who say stuff like that tend to have an inherent and twisted need to lord over everything and everyone around them. Dogs bend the knee, so dogs are okay. Cats are independent and won't bend the knee, so cats are labeled as selfish and uncaring. And so many of these cat disparaging dog praising souls are much the same with people. So watch out for them. Loads of Americans like that.
You know, there was a cat who was recently credited with saving the life of an baby abandoned outside in the winter by curling up with the baby to keep the baby warm and mewing its little head off until someone took notice. Yeah, those self-centered cats.
And to anyone who will make the counter claim that cats have killed babies, dogs kill and attack loads of kids, and if the media is any guide, dogs do it way more often.
And this is from someone who got the hell scratched out of him by cats when he was a kid. I did not just sit there and sulk and expect the cat to bend to my will. My family would not allow that. They explained to me repeatedly that I was not gentle enough and I was hurting and scaring the much smaller cat. I learned. Dog lovers only know that their dogs have quite a threshold for pain and are therefore less hassle for the dog lover.
As for the obsession with cats in Japan, its important to realize that this is the manga world we are talking about. Hand-drawn cats are easily recognizable, unlike say, an hand-drawn possum.
Real cats are not that well like in Japan. Lots of strays and lots of abused cats. Dogs are revered. But is that a surprise from a nation that conquered all her neighbors and just kept rolling with the domination game? No. I don't think so. However much Japan has not launched wars in 70 years, in some ways they are the same as they were then. They have a sense of superiority, self-importance and think other people's ways are mostly explicative. They still have a strong sense of lording over others, only its now more visible in their corporate culture.