That is not what the objection to her qualifications are. The objection is that she should be a really smart lawyer as demonstrated by something she has done. Her so-called record has been combed pretty thoroughly, and there is no evidence that she is a really smart clear-thinking lawyer. Also, a background in constitutinal law is a requirement because what SC judges do is interpret the Constitution. It is a pretty brief document, but thorougly grounded in princples from English common law, the Federalist Papers, and other writings of our founding fathers. The constitution does not just say what it says and nothing else.
I guess it depends what you mean by qualified. Normally, a president should nominate the best candidates available. Whether they want a knee-jerk Roe v. Wade supporter or a strict constructionist, they should still nominate the best in these categories. I don't think that's the case here. There are probably thousands of corporate lawyers who are equally well qualified--which is to say, not qualified--for such a cricial job.
In any case, the doubts about her conservatism, and the many small bits of evidence to the contrary, are more important. Better a second-rate conservative than a first-rate liberal; but best of all, a truly stellar conservative.