People seem particularly prone to holding on to caricatures of political figures even after the evidence strongly suggests the caricatures are incorrect. I think most of the Supremes are not adequately captured by "conservative/liberal" or "dumbass/intelligent" (for suitably egocentric definitions of "intelligent").
In this particular case, I think you have a poor sense of what "original intent" argumentation is about. Original intent arguments don't actually center around what the founders "envisioned" in the sense of their ability to imagine the future. It's much more like, if we took the founders and educated them about the present, what would they think? It's a challenging thing to do, but perhaps not impossible. It's not hard to imagine them agreeing video games are a form of speech, given the diversity of forms speech had even in the late 1700s.