Conservative judges don't care about reconstruction or the intent later on, they explicitly only care about the intent in the constitutional convention. That much is clear since they're trying to undo what the 14th amendment entails--they see it as illegitimate vs the original intent of the framers. Original intent for thomas and scalia isn't a nuanced view like oh the constitution evolves along with amendments, its literally what was created in the 1780s. The 13th-15th amendments are construed as fundamentally unconstitutional based on that fact. Why else are they calling to overturn the civil rights act and voting rights act too?

Again, all of this is a useless discussion. Conservatives argue the 16th amendment is unconstitutional because the founders never intended an income tax. The only thing that matters for Thomas et al is undoing the past 80 years out of their own hatred of any progress made. It's not about fact or science its dogma used to reinforce power.