I think you're more right than wrong. The reason for that is that Masterpiece and Fulton have already sort of sent the message that the regulators have to tread very carefully on a 'facts and circumstances' basis when it comes to enforcing public accommodations and other public benefits laws where religious objections may be implicated. As such, there's not 'really' a need for this case to be heard, other than a desire to try to establish a more categorical rule.
The problem (if that's the right word) is that putting together a categorical rule that is premised on free speech considerations rather than free exercise considerations could open up a real can of worms when it comes to defining what types of businesses actually involve "speech activity".
Well didn't the SCOTUS essentially punt on the Masterpiece case anyways by basically saying they discriminated against him because in the hearing they mocked his religion?
I think basically everyone is looking for a more definitive ruling and Alliance defending freedom saw that now was a good time to get that definitive ruling because of the court's composition.