No, the First Amendment should not be used to protect all religious practices. Some practices would inevitably infringe upon another’s inalienable rights such as life, liberty, and protection of property. These would be externalities to the individual that the government has a legitimate role in regulating. So for example, human sacrifice or child sacrifice is indefensible as a practice because it would impose an externality upon another person and deprive them of life apart from due process of law. That being said, the First Amendment was enacted to protect individuals from government interference, not to prevent the individual expression of religious values in the public square. So the establishment clause prevents the government from establishing an official state religion that it would compel individual citizens to obey; simultaneously, it prevents the government from infringing upon the free exercise of religious values in the public square. If we hold to the original intention of the First Amendment, then a business should have the right to refuse service for events that it deems to be objectionable. Unfortunately, the 14th Amendment has been coupled with the regulation of interstate commerce in a way that far exceeds the meaning of the laws and the original intention of those two clauses. Essentially, many rulings of the Supreme Court throughout the years have essentially read into the law whatever the majority opinion felt like reading into it, instead of reading the law as it was initially written and putting the onus on the legislative branch to change the Constitution. That being said, even with the illegitimate reading of case law in the past, a small business owner, while not having the right to refuse business for the purpose of not serving a particular class of individual based on race, sex, age, religious affiliation, etc., should still have the right to refuse service based on the type of service being requested. If I am cabinet maker and someone asks me because I have a background in carpentry or a related to field to do the framing of a house, I should be able to refuse because I object to providing my labor for that purpose. Same thing with designing cakes or floral arrangements for a purpose to which I am morally opposed. The government does not have the right to compel my labor (without due process) or speech (First Amendment).