It's sad to see that people have so little interaction with animals that it seems that some people immediately equate big dogs with being 'dangerous'. Here's an interesting article in today's Straits Times :-
Animals have more reason to fear humans than we do to fear them
I've grown up with 'big' dogs for most of my life, but the first dog I've been nipped by was a friend's terrier (and it was entirely my fault - I pet him when he was fast asleep and he reacted instinctively). Big does not immediately equate dangerous - as the writer mentioned, Labradors are some of the most gentle dogs, but they are large dogs, but I don't think they would be used as guide dogs for the blind, except that they have such excellent temperaments.
It's the same with cats - people are growing up in such an isolated urban bubble, that they have forgotten what it is like to interact with animals. This really reminds me of Budak's comment about his friend's blog.