You're not alone in your confusion there, friend. Reading Speaker for the Dead and finding out about who the author was as a person blows my mind as to how such a bigot could even conceive of the ideas in that book.
Unfortunately the USA has been fed a steady diet of nationalism branded as Patriot Juice with extra Freedom for a long time and too many people have been drinking at the trough.
Just trying to help where I can through pedantry. Had someone this morning use "all intensive purposes" and he was amazed at how much more sense the actual phrase makes. Recontextualized things for him a bit.
Humans are not the only animal that sheds tears. Note they specify emotional tearing is considered uniquely human but do not specify tearing as uniquely human. Plus they studied tears in mice as stated in the beginning of the abstract.
Emotional tearing is a poorly understood behavior that is considered uniquely human. In mice, tears serve as a chemosignal. We therefore hypothesized that human tears may similarly serve a chemosignaling function. We found that merely sniffing negative-emotion–related odorless tears obtained from women donors induced reductions in sexual appeal attributed by men to pictures of women’s faces. Moreover, after sniffing such tears, men experienced reduced self-rated sexual arousal, reduced physiological measures of arousal, and reduced levels of testosterone. Finally, functional magnetic resonance imaging revealed that sniffing women’s tears selectively reduced activity in brain substrates of sexual arousal in men.
They're making the landing even softer