I have to say, I agree. Even as a kid I noticed my own tendency to regard dogs as male and cats as female (which is odd, coming, as I do, from a culture without gendered nouns).
On the other hand, despite having size and weight advantages over cats as you describe, dogs generally don't actually eat cats. So it would be easy in an anthropomorphic sense to imagine dogs as being at least slightly more benevolent towards those weaker than them than cats are.
Of course, there's also this as a possible explanation.