Slavery 

The institution of Slavery runs counter to the Masonic ideals of universal love and the equality of all men before God.

A slave, however, cannot become a Freemason because the slave, by definition, does not have freewill as the slave is owned by another.  If the slave has no freewill he can not join Freemasonry on his own will and accord.

It is said by many that slavery was the cause of the Civil War in America, but slavery seems to have played at most a very minor portion when compared to the rights of the States.

It is said by some that Freemasonry and the Knights of Christ were involved in the slave trade. See "Secret Societies of America's Elite" page 4)  Perhaps some Masons were involved in this activity, which was legal at that time, being endorsed by both government and religion.

While slavery was not a good thing one must remember that in the past it was legal in most of the world and was approved of and encouraged by the major religions including Christianity, Judaism and Islam.  This was true not all that long ago.