I'm afraid I have to disagree, and rather agree with Lisa's point. Female figures throughout history, as pointed out, have been far more commonly maligned simply because they were in positions of power, than their male counterparts. Both in a modern context (Clinton, or indeed Margaret Thatcher being good examples), or in ancient history, for example Cleopatra, women are often targeted in very specific ways. Cleopatra for example, or indeed, Catherine II, were not particularly more brutal or bloodthirsty than their male counterparts, and yet are depicted as being so. CII introduced remarkable reforms, and yet in popular history her fictitious sexual escapades are projected as more important, interesting, and central. The idea of this kind of negative imagery around sexuality being attached to a male Tsar in the same way (Alexander II for example, known for his string of mistresses) is difficult to imagine.
Even historians who take a far more right wing approach, would be hard pushed to suggest that men have had it more difficult than women historically.
More specifically in reference to Nicholas and Alexandra, the question is, was his behaviour not 'ripe for criticism'? Alexandra was certainly a difficult figure, but she was, after all, not the ruler, and yet history commonly depicts Nicholas as bumbling and incapable with good intentions, whilst Alexandra as shrewd and villainous. It seems to be, as Lisa pointed out, unfortunately part of the dialogues around women, even today.
Moreover, as Douglas Smith makes point of in his work on Rasputin, it is all too easy to overestimate the amount of Rasputin, and indeed Alexandra's, involvement in politics. Both Vyr. and Bux. state on more than one occasion that Rasputin was by no means as often in the presence of the imperial couple as has been suggested, particularly during the crucial war years. Indeed, even when looking at the Tsar's diaries, his references to seeing Rasputin or hearing from him in no way support the imagined significance of his power. Can some of this lore not be attributed to the same depiction of the Empress built upon outdated gossip and outdated misogyny?
Moreover, the historical record is surely always skewed, always grounded in some historical source, context, and ideology, and we must surely be careful to take these sources as the undiluted truth.
It is an interesting idea that women might be the source of more suspicion or judgement because they are seen as having to twist and manipulate their ways to the top. I wonder to what extent one might see this as the case with the Empress.