I disagreed with the Dred Scott ruling at the time it was made ...
SCOTUS was wrong.
It’s OK to say it.
The thing is that he indicated that he is opposed to Roe vs. Wade, so he admitted the court was wrong in that instance. He could say, as he said when was campaigning, that he believes the court was wrong in the instance of gay marriage. When he was campaigning, he said it should have been left up to the states.
Of course there are people marching in the streets now, and one of the groups is LGBT, so to say he’s putting justices on the court that will definitely overturn it when there is no way of knowing that (and when there is a lot of support for gay marriage in this country - more than for Roe vs. Wade), would likely make things worse from a protesting standpoint.
Dred Scott was a technically correct ruling based on the Constitution. That doesn’t mean it was morally correct. The “gay marriage” issue was different. It was not only a false and unconstitutional ruling, it was also morally incorrect.
If Republicans are not going to support social conservative issues, who will?