The Next Civil Rights Crusade
There are limitations to the legal recognition of artificial persons. Legal entities cannot marry, they usually cannot vote or hold public office,Corporations cannot marry? Does that mean if you've fallen in love with the corporation of your dreams, you cannot marry him/her/it? THIS IS UNFAIR!
and in and in most jurisdictions there are certain positions which they cannot occupy. 
Legalizing corporate marriage is the next logical step after gay marriage and polygamy. (Marriage to animals, vegetables, or minerals will have to wait.)