If you are married to the King you become the Queen (+ name) as has been the case throughout our history - Caroline, Charlotte, Alexandra, Mary, Elizabeth (whom we knew as the Queen Mother, but within Palace circles was referred to as Queen Elizabeth to distinguish her from THE Queen after the latter's accession)
You don't earn the title or have to "deserve" it in anybody 's eyes. Every wife or partner of the monarch is technically their Consort -and the title of Prince Consort was in common use with regard to Prince Albert. Perhaps the exception was William and Mary who ruled equally.
I don't see why some people are getting so uptight or judgemental about it. It was a nod to the strong pro-Diana popular opinion of the time that Camilla was never called Princess of Wales, although, technically she was that person by dint of her marriage to the PoW.
Like it or not, and some clearly don't, but it is what it is.