To say that using sex or race or creed as a factor is 'racist,' 'sexist,' etc. - since no one can plausibly claim to go about life not noticing and responding to those factors - is to render the words as meaningless as saying that a President who takes personality into account when choosing a judge is a "personalitist."
As far smarter people than I have said before, 'racism' or 'sexism' isn't about being conscious of race, since we all are, but whether one's actions are aimed at 'subordinating' one person or group on account of that factor.
For sure, to factor heavily gender in this case will be to the advantage of men; however, by choosing a woman because she is qualified and a woman is an anti-subordinating act as women are almost completely unrepresented on the High Court. Nor can it be said that by the adding of a second female Justice out of nine, the President is acting to subordinate men. This is all the more important for an indirectly chosen position. If Congress is predominantly men, people can change that if they choose. However, the Court is different - and for a President elected because of women to choose not to increase their representation on the Court would be... backwards?
And as for the "brilliant" comment, I suppose I just have a different standard for "brilliance" than Justice O'Connor - and Roberts ain't it. Indeed, I can think of no one currently on the Court I would consider brilliant - very smart and conscientious people, yes, but brilliant? No. A brilliant person is almost by definition paradigm-shifting. Plenty of good, smart, decent leaders weren't brilliant - Washington, Adams, Reagan, FDR, Marshall, and so on. So, in short, don't let a little overexuberant praise make you think there are some vast distinctions in the quality of the potential appointees...