Because if not then apparently the main game I moderate (GTA Vice City) is just stuck with PS2 being the top (default) option even though the vast majority of runs are done on PC.

Yeah unfortunately there's no way to reorder them, they're just sorted based on some internal ID or something. Would be a great change to allow reordering them, or at least setting a reasonable default (or, frankly, even just make sure that PC is always the first one, the vast majority of games that are on PC are mostly run on PC).