I have heard this a lot as well. I have found though that they tend not to like the breeds that are hard to read. Such as Shar pei's, boxers etc who have squished faces, short tails, lots of hair etc. Basically anything physically different about the dog that makes their intentions hard to understand can make other dogs very wary of them. Especially if they have not met the breed before or did not meet them often as puppies.
"In order to really enjoy a dog, one doesn't merely try to train him to be semihuman. The point of it is to open oneself to the possibility of becoming partly a dog." - Edward Hoagland