That's got to be one of the most ridiculous things I have ever heard.
Killing someone will never considered right, now or even in the future. It is morally wrong, and those of us with a conscience would never stand for it. God said, "Thou shalt not kill", and His Word is ETERNAL. It does not and will not change. To compare slavery, where some slaves were killed, maimed, and tortured, to the voluntary termination of pregnancy is completely farfetched. For one, the slaveowners knew very well it was wrong; they used the bible as tool of oppression towards to the slaves.
Aborted fetuses are not being freed, they are being killed. The two ideas are not even connected in the remotest sense.