Originalism is a deliberate interpretive choice. It's not the only the means of interpreting constitutional text and its relatively new compared to other forms of interpretation (Brennan / T. Marshall "living constitutionalism"). It really hit the legal mainstream under Reagan, championed by Scalia.
To interpret the Constitution under originalism is to disregard most, if not all, historical and legal context that has occurred in this country since its ratification. It seeks to enshrine law and the definitions of terms in the Constitution perpetually in 1783 or 1865 (ratification of the Reconstruction Amendments). There is no evidence, that I've run across, that any of the Federalists or drafters of the constitution were under the illusion that the Constitution was a static document. J. Marshall directly states that it is not, and since Madison wrote the damn thing, you think he would've argued the point in Marbury. He didn't.
In practice, originalism does not seek to protect civil rights. The only civil rights that originalism has successfully "protected" have been 2A rights (which are relatively new in historical interpretation) and putting its thumb on the religion side of the state / religion scale. I can assure that modern 4th Amendment jurisprudence does not reflect 1783 realities, for example. How the hell could it?
Most civil rights, as we know them, have been derived by judicial interpretation of the 14th Amendment (substantive due process). There are problems with the way the Court has defined those rights and where they "come" from (the first substantive due process case was actually Dred Scott), but originalism works against substantive due process, not with it. It's a legal response to the recognition of all sorts of civil rights under the 14th Amendment in the post-WWII era. It was "invented" strictly as a means of limiting constitutional scope and protections. It's a more educated Rush Limbaugh telling you the Constitution doesn't technically offer protections because they are not enumerated verbatim. That's not what the Constitution was, is, or was ever intended to be. At least not to my eyes.
Scalia, and others, have argued that it is meant to force legislative responsibility back on Congress, rather than have the judiciary be the final arbiter of what can be interpreted out of the 14th Amendment. In other words, Congress should pass laws or Constitutional amendments codifying interpretations of civil rights, so that they cannot be taken away by later Court opinions (like... abortion). That sounds nice in theory, but we have used the Court as a political proving ground going all the way back to Marbury. The amendment process is more or less dead in our current political gridlock (ERA been on the block for... 40ish years now?). It would be nice if we relied on judicial interpretation less, but its been baked into the system so to speak. There was never in any real chance that the federal government would suddenly become better legislators because a few hardcore conservative justices decided to be pedantic dicks about everything and go out of there way to make life for many Americans harder than it needs to be, and it's already hard enough for a lot of folks.
Originalism is the trickle-down economics of constitutional interpretation. It's spun up bullshit to keep certain interests in power perpetually. The shinejob that the Founders never intended the Constitution to be interpreted in a context outside of their own is a marketing ploy to conservatives to make them feel better about fucking people over legally.
Finally, the ultimate irony of originalism and its prohibition on substantive due process is that gets tossed out the window by Scalia, its chief proponent, when he goes looking for constitutional protections for the 2nd Amendment in Heller and and for religion in Hobby Lobby. Like every other weapon in the conservative's limited arsenal, it is not meant to be equitable. It's just another power grab under shoddy veneer.