Does it happen in every world? Mine with calamity+thorium+spirit+crystallium+alchemistNPC is loading a few seconds longer than without the mod. I think that your issue may happen on low end PC if you have mods which add a lot of items. There is a code that runs after world load (in PostUpdate) and analyzes which tiles are created by which items to find all crafting station items and it has to go through all available items as there is no game database to simply query it. It's required to not show recipes which require crafting stations unavailable at your current progress. Normally this run takes 1-2 seconds.
You can try commenting the PostUpdate
here.
Also I reverted some changes in the pull request but you can access my full version
here (but you already have its build, right?).