Given that, even assuming an originalist position, there is little in the Constitution that is self-evident in terms of meaning, given the wide variety of circumstances to which it may be applied, such that act of judging what original intent was is itself an act of projecting one's own understanding (informed by one's bias) on the meaning of the Constitution.
I wonder how many of the truly progressive rulings that have extended application of civil rights/liberties would have happened under an originalist interpretation of the Constitution. In my view, some things, such as civil rights/liberties, are too important to be left to state legislatures, which are often dominated by parochial local factions/power structures.
As a practical matter, originalism doesn't work for me. The Founders could in no way anticipate the complex nature of society in modern times, and thus I see it as essential that we can take the general framework laid down by the Constitution and figure out how to apply it to modern situations. I see nothing wrong with this at all, or with 'judicial activism,' which, when invoked, is typically invoked to criticize rulings one disagrees with, as opposed to stating a general and consistent judicial philosophy.
Of course, the risk with judicial activism is that it may swing against your interests at times, but then so might originalism. There's no guarantee either way. For example, I see Citizen's United as a case of 'judicial activism,' which will have the effect of, essentially, disenfranchising votes relative to the power of corporations or large political donors, but it's one I can live with, because, while some might think Obergefell is also a case of judicial activism, it is one I agree with and I that believe is an important extension of civil rights. It's a trade-off, but so are most things.
But then I'm hardly a legal scholar so take all of this for what it's worth.
