The PSU and the LCL from corsair are 2 different things altogether. One is not connected to the other and unless some wires have been screwed or have got wedged between the mobo and the back mobo mounting panel, you shouldn't need to use excessive force to get them out.
Just need to make sure that all those wires from the PSU to the mobo are locked in with clips that latch onto the sockets on the Mobo. Make sure to press down on those clips to free the locks while pulling the wires out or you will end up braking something.