1. Does the Bible prohibit it? If you think that it does, just how explicitly does it do so? Does it call it an abomination like homosexuality (or male prostitution, if you want to split hairs) or the sacrifice of infants?
Lots of myths accept all sorts of weird/unhealthy/cruel behaviors and ideas... The Bible has stories of slavery, concubinage, abuse, slaughter, destruction of innocent children, etc. etc. etc. etc. etc. etc. etc.
2. Does the Bible condone it?
See above... It may suggest something about the Bible.
3. Is your revulsion to plural marriage based upon some extra-Biblical norm? If so, what is it?
My qualm with a married man sleeping with multiple women has to do with the beauty that has come forth through monogamous relationships. The depth, intimacy, care, love, sharing, etc. etc. etc. that is exclusive to the human is impossible when a man is sleeping with many woman. This form of mating is primitive and animalistic and not representative of the continuing unfolding of humankind.
4. If you are willing to accept the notion that the Lord can and has permitted plural marriage, can it be abused by men? If so, whose fault is that?
There is nothing Godly about procreating like animals rather than sharing intimacy like evolved enlightened human beings.
5. Finally, what do evolutionary biologists say? Is plural marriage the norm or the exception for homo sapiens in the history of man?
While polygamy has been allowed since the time of ownership of women, evolutionary biologists are consistent in the fact that it is rare in its practice. Monogamay has evolved for very clear reasons... it is healthier for our species in every way. Children, women, men and society are damaged when human beings revert to a primitive style common in the animal world. (See Jared Diamond, Why Sex is Fun, Guns, Germs, & Steel, Robert Wright, The Moral Animal, David Buss, The Evolution of Desire... for starters).
A man impregnating women to spread his seed is nothing more than an animal.... the universe has brought forth, in the human something amazing and utterly incredible in the form of intimacy and the beauty that can exist in a healthy monogamous relationship.
~dancer~