There seems to be some misinformation creeping into this thread.
Below are the facts, as recorded by the Colorado Civil Rights Commission in its 2013 decision on the matter. In particular, note items 4 through 8. You can read the entire document at the link.
1. Phillips owns and operates a bakery located in Lakewood, Colorado known as Masterpiece Cakeshop, Inc. Phillips and Masterpiece Cakeshop are collectively referred to herein as Respondents.
2. Masterpiece Cakeshop is a place of public accommodation within the meaning of § 24-34-601(1), C.R.S.
3. Among other baked products, Respondents create and sell wedding cakes.
4. On July 19, 2012, Complainants Charlie Craig and David Mullins entered Masterpiece Cakeshop in the company of Mr. Craig’s mother, Deborah Munn.
5. Complainants sat down with Phillips at the cake consulting table. They introduced themselves as “David” and “Charlie” and said that they wanted a wedding cake for “our wedding.”
6. Phillips informed Complainants that he does not create wedding cakes for same-sex weddings. Phillips told the men, “I’ll make you birthday cakes, shower cakes, sell you cookies and brownies, I just don’t make cakes for same-sex weddings.”
7. Complainants immediately got up and left the store without further discussion with Phillips.
8. The whole conversation between Phillips and Complainants was very brief, with no discussion between the parties about what the cake would look like.
9. The next day, Ms. Munn called Masterpiece Cakeshop and spoke with Phillips. Phillips advised Ms. Munn that he does not create wedding cakes for same-sex weddings because of his religious beliefs, and because Colorado does not recognize same-sex marriages.
10. Colorado law does not recognize same-sex marriage. Colo. Const. art. II, § 31 (“Only a union of one man and one woman shall be valid or recognized as a marriage in this state”); § 14-2-104(1), C.R.S. (“[A]marriage is valid in this state if: . . . It is only between one man and one woman.”)
11. Phillips has been a Christian for approximately 35 years, and believes in Jesus Christ as his Lord and savior. As a Christian, Phillips’ main goal in life is to be obedient to Jesus and His teachings in all aspects of his life.
12. Phillips believes that the Bible is the inspired word of God, that its accounts are literally true, and that its commands are binding on him.
13. Phillips believes that God created Adam and Eve, and that God’s intention for marriage is the union of one man and one woman. Phillips relies upon Bible passages such as Mark 10:6-9 (NIV) (“[F]rom the beginning of creation, God made them male and female, for this reason, a man will leave his father and mother and be united with his wife and the two will become one flesh. So they are no longer two, but one. Therefore, what God has joined together, let not man separate.”)
14. Phillips also believes that the Bible commands him to avoid doing anything that would displease God, and not to encourage sin in any way.
15. Phillips believes that decorating cakes is a form of art and creative expression, and that he can honor God through his artistic talents.
16. Phillips believes that if he uses his artistic talents to participate in same-sex weddings by creating a wedding cake, he will be displeasing God and acting contrary to the teachings of the Bible.