Everybody is right here, because we haven't defined the meaning of the term "gold standard" as it relates to PCa.
If it means "generally accepted as the best treatment for most", then surgery has certainly had the title in the past, and I think still has. It takes a while for new treatments to be generally accepted and having a track record going back many years sure does help.
Modern, closely targeted radiation with HT shows promise. But does it kill all
prostate cells? I don't think it does, since I haven't read of PSAs dropping to undetectable after treatment, as often happens with surgery. What happens if the prostate cells that survive later turn cancerous? Can we have do-overs? How good is it in avoiding collateral damage? Those are questions I would have.
Undoubtedly radiation with HT is the best treatment now for some men, but by my definition above, it is not yet the gold standard. If you want to define the "gold standard" some other way, then I'm sure you could make a definition that gives the title to radiation/HT, or indeed any other treatment.