Well, think about it this way: Our closest relative, in the same family and, according to some, should be in the same genus, is the Bonobos.
HOWEVER, if we are talking about social structure, we are more like the Gibbon. Some could argue that we aren't even related to the Gibbon, because we are in different families (although we share the same infraorder).
Gibbons pair bond, have have nuclear families consisting of a dominant male, a dominant female, and their young. Children tend to leave when they are sexually mature, and go find a mate. There are instances of "divorce", and changes of mates, as well as uncommon instances of polyandrous or polygamous matings; but normally, what they have is a male and female pairing, and their kids.
Bonobos have a female dominated society, and they have sex for EVERYTHING. When they meet other groups, they have sex. When they groom each other, they have sex. They have sex with same AND opposite sexes. They have sex before they argue. They have sex to make up after they argue. Juveniles have sex, with each other and older Bonobos. Most of their interactions involve sex. If they find a fruit laden tree, they get so happy about it, they have a group orgy. Considering their groups can number 100 members, that is a LOT of sex!
So, if I say that our (meaning human's) social and family structure most closely resembles gibbons, rather than our more genetically closer relatives such as the Bonobos, the Chimpanzees, and the Gorillas, I am not saying that I think we are Gibbons, or that *everything* about us is more like Gibbons than Bonobos. I am simply saying that if we wished to make comparisons about social and family structures, we would be able to make more with Gibbons than with Bonobos, or even, for that matter, Gorillas.
So, when I compare the diets of deer and goats, I am not saying that deer and goats are super closely related, or that deer are more closely related to goats than sheep are; I am simply saying that their *diets* are more comparable than between sheep and goats.
And, of course, I must say that one cannot state that there is NO relation. They are, of course, in the same infraorder, therefore, they are, indeed, related. Just like we are related to Gibbons. Just not as closely related to them as we are to the orgy-loving Bonobos.