His reference to "Jim Crow" laws is that diecasts are "segregated" into their own category, and he doesn't like it that way. Since modifying diecasts is very different than modifying plastic kits, we decided that a separate diecast section makes sense... both to accommodate the diecast builders and collectors who are forum members, and to avoid "offending" those people who think that diecasts aren't legitimate scale models.
He doesn't like the fact that we have a diecast section and that his thread was moved there. It all falls under the category of "You can't please everyone" or "No matter what we do, there will always be someone who's going to complain about it."
If he's offended in some way that we have a diecast section, and that his diecast modification thread was moved to the diecast section, and so now he's going to stop posting on the thread to show us all how unhappy he is about that, well... that's his call.