The birth control argument is rooted in religious freedom, as is the argument that a baker should not be required to bake cakes celebrating something he believes is evil. If they support religious freedom here, it will be harder to deny religious freedom to those who object to homosexuality.
Either we are or are not free to act in public based on our religious beliefs, and so are the businesses that we form and own. You cannot logically be free to have a religious objection to abortion, but not a religious objection to homosexuality.
That's why it will be narrowly decided on the basis of exemptions to regulation granted others under ObamaCare. That way it won't apply to the baker/cake issue.
Of course you can. Just laws in a free society only prohibit actions that interfere with another's life and liberty. Unjust laws interfere with adult individuals' own private free choice that does not interfere with other's freedom.
Abortion is murder, clearly interfering with the life of the unborn and, therefore, should be prohibited.
Sodomy done in private between consenting adults, though deviant and reprehensible behavior, does not interfere with another's freedom and, therefore, should not be illegal