Most problem with the side stand switch is from corrosion of the contacts inside the switch Quite possible that the replacement switch is faulty also. Have you checked the replacement switch with a meter or test lamp?
Contact cleaner or WD40 sprayed into the switch from the moving piece and operating it many time should get it working again.
Try bypassing the side stand switch by looping the two wires in the wiring loom side connector and see if it starts.