SCOTUS did not rule that baker’s refusal to bake cake for same sex couple was constitutional. Court ruled the CO Human Rts Commn tribunal that ruled against the baker in MASTERPIECE CAKESHOP was not neutral but hostile to the claim. Baker was entitled to impartial decisionmaker.
It’s a narrow ruling.
It’s fair to say the Court ruled “for the baker,” but not in the way that phrase implies. Perhaps more accurate, the Court struck down the decision of the CO Human Rts Commission b/c a majority of justices believe the baker did not receive a fair hearing.
Perhaps reading the end of Kennedy’s opinion will help: 
Obviously we are not out of the woods yet. The core question remains unresolved for future cases.
The decision is grounded in the particular facts of this case. In terms of the broader issue of public accommodations & religious exemptions, the Court offered reaffirmation of the core nondiscrimination principle of Obergefell & strong reaffirmation of Piggie Park:
Nevertheless, it’s disappointing. Justices Ginsburg & Sotomayor make a strong case that the CO Commissioners actions do not justify reversing on these facts.
