Originalism is bullplop because the Constitution is NOT a monument to the "genius of the Founders". The idiotic Founders made stupid assumptions such as that Europe would remain full of absolute monarchies eager to subvert the USA and they treated enslaved blacks as worth three-fifths of a white person.
I would agree that the Constitution is not a monument to the "genius of the Founders," as would most mainstream Orginialists; it's a legal document that sought to provide the basis of a workable republican government. To that end, most originalists don't actually care what the framers of the Constitution thought, rather they are concerned with the original public meaning of the document. As with legislative intent as a tool of modern statutory interpretation, trying to understand what the framers meant as it relates to any given Constitutional provision is a fruitless task and subjects you to the nonsense about hidden meanings and related absurdities.
So, if the document is not some document of genius (and it is not, as discussed above) then you can't say that it can be used in its present form to provide certain rights that can not be reasonable ascertained in the original public meaning of the document and its amendments. If anything, it is the critics of originalism who hold up the Constitution as some work of genius, so genius that it simply serves as a vehicle for the transcendent values of the framers. Originalist recognizes that the framers were white, property-owning men of another time and thus that their words cannot be used to justify everything under the sun as having Constitutional protection. This is also true of later amendments—which contrary to much public ignorance originalists do not reject—which were also written and ratified by men (and eventually women) in different times and circumstances. That specific amendments and provisions in the Constitution are responses to particular problems and circumstances is at the very heart of Originalism. I recognize that many (if not most) adherents of the "living" view of the Constitution would take issue with my characterization of their views here, but I think it serves to show that ultimately it's nonsense to assert that Originalism is bound up in a view of the Constitution as a flawless charter when it is, in fact, a pragmatic realization of the exact opposite conclusion—that it is a crafted by men for the purposes of forming a government in a particular time and place and that we must read it in that context. In some form or another, I think that assertion lies at the heart of most legal scholarship. While some see this as a reason for judges to update the text as they will, Originalists simply see it as a logical limiting principle to prevent judges from imposing their political will through the legal system.
It also didn't start with Scalia. Here's an Article Robert Bork wrote outlining some key arguments in favor of what we would now call Originalism in 1971:
https://www.repository.law.indiana.edu/cgi/viewcontent.cgi?article=2720&context=ilj
