Anthropomorphism is the ascribing of human characteristics to animals. It is flawed process.
The fallacy in your argument is that we already have "love is love". Heterosexuals love each other. So following your logic you are saying that because we allow heterosexuals to marry that the next thing will be that they will love and marry their dogs. Have you felt the urge to straddle a chichihua? If you haven't why would you assume this of others?
