I agree, LadyFinn. And Boris' post identifies the difference/center of criticism with Sofia. With some of the other girl/boy-friends who eventually married into royal families fame is something that only happened after their relationship/marriage. For example:
Mette-Marit - the one that is most often compared with Sofia. Nothing in her prior life suggests she sought fame. It came along with her relationship with Haakon. She even had to publicly acknowledge her mistakes and "apologize" in the press conference before the wedding.
Mathilde - was probably the "most acceptable" of the current crop of princesses. Well-mannered, intelligent, educated, stylish, etc....but none of her actions demonstrated a desire for fame. Quite the contrary as she seems to be the most quiet of them all.
Daniel - perhaps struggled the most publicly with the attention prior to the wedding and perhaps endured the most criticism/ridicule for his alleged "shortcomings" as a possible prince. Since then has demonstrated the most professionalism, poise and commitment to his spouse and duty, even if completely outside of his life-goals before.
Diana - like/hate her, she endured the most scrutiny and attention of any and was one of the first in this generation to recognize and use the media - not always correctly but most effectively for others.
Letizia - even though she was in the public eye, it never seemed she sought fame or used her relationship with Felipe to further her own agenda, in fact the world knew nothing about her relationship until the engagement announcement. She seemed more concerned with being a journalist than famous.
And all of them, even though criticized initially were accepted not only because people in general believed that they made their royal spouse happy but because people believed that these individuals would enhance the royal family or at the very least not be a detriment to the monarchy.
With Sofia it is clearly different - even if there were never any questionable pictures, the true problem and the one which IMO causes the greatest concern is that from a young age she has clearly stated a goal - to be famous. The nude pictures were just one poorly-chosen attempt to achieve that. The impression is that she pursued CP not for who he is or because she loved him, but rather because it would provide her with a higher level of fame. Knowing that, people who criticize her may believe that her feeling for CP are insincere. And they may feel that her ambitions and actions are damaging to the monarchy. THIS is the criticism that repeatedly has gone unanswered by Sofia's supporters. Not once has any of them addressed this aspect of her personality. Rather they accuse anyone who raises any criticism of hating/judging her unfairly because of the nude pictures.
Obviously this post and the others regarding Sofia belong in a different thread, but as she has taken to attending official events with CP I replyed here. Again, this has not been done by any others. None of the others attended any official engagements of their royal spouse prior to engagement. Even Daniel, when attending private events with their mutual friends did not arrive with Victoria...and he was the most recent one.
Regarding this thread, I feel that it is irresponsible for CP to have Sofia along on his official events. In addition to taking focus away from the issue/event at hand, I wonder if he gives his full attention/support to that event. Not that I support her or think he should get back with Emma Pernald, but she never did this...probably because she had an actual job and actual life to attend to away from CP...like an actual couple.