PA laws are bought into when one opens a business that is defined as Public Accommodation. No one is forced to open such a business and if they choose to do so they can put up a sign that says "I hate fags" and be as bigoted as they like. The choice is theirs.
Christians don't hate fags. In fact, in the same passage that promises eternal damnation for enabling the spread of homosexuality
as a culture, the Christian is told to reach out
to individual homosexuals with compassion "making a difference" (Jude 1 of the New Testament). The problem for Christians is the culture, not the individual. The hub of any culture is marriage. So there's where the problem is.
It could be a wedding cake, wedding photos, wedding flowers, wedding catering...but for a Christian combining the word "wedding" with "gay" or "homosexual" is strictly forbidden. The punishment is eternal torture of the soul. You cannot require any person to submit to that as a requirement of opening a business.