It's persecution of Christians by the US state. This is precisely what the First Amendment was intended to prevent, i.e., to interfere with the free exercise of religion.
The 1A says that congress shall make no law prohibiting the free exercise of a religion. This isn't congress. It's the state of Oregon.
You're forgetting Fourteenth Amendment incorporation doctrine. That said, forcing them to bake a cake for someone also violates our right of free association (not to mention our Thirteenth Amendment right against involuntary servitude), not to mention basic property rights, i.e., if I wish to sell my goods only to blue eyed, blonde haired people, that's my right, stemming from the fundamental right to property.
