I do not understand how liberals can defend Justice Ginsberg's initial remarks, let alone her doubling-down the next day. "She has the 1st amendment right" is a non sequitur because she was not speaking in her private capacity. She can do it with her family, friends, and colleagues, and few will bat an eye even if those conversations leaked out. But she consciously chose to speak out in a setting where she was giving an interview as the SCOTUS justice.
It is also a misguided defense to say that "Everyone already knows what she believes in, so what is the big deal?" Well, for one thing, one's spoken words tend to reinforce one's thoughts, consciously or subconsciously. We all have a sense of honor, and want to avoid being seen as a hypocrite. When justice makes a public comment on a political issue, she may have limited her future opinions on similar issues for fear of being seen inconsistent. That is why we require judges to maintain appearance of neutrality - because the court's legitimacy depends on it, and because languages are not mere expression of thoughts. They also reinforces ones previous thoughts.
I frankly have no idea what her intention was. She is an extremely smart person and by all accounts her remarks were not a momentary slip in the heat of discussion. She must have weighed the cost and risks of her speaking out, and I wonder what convinced her to go on with the plan. What did she deem such an urgent issue that she would go out of the established norm, fully aware that her comments will attract backlash?