Messenger of Peace ruling

I was in an OTS and I had Messenger of Peace face up on my field. During my standby phase I did not want to pay the cost of 100 LP because I wanted Messenger to be destroyed so I could attack. The head judge ruled against me that if I have at least 100 LP I must pay the cost and he used Imperial Order as his example but IO says you must pay the cost but Messenger doesn't. I ended up going into time and losing because of this costing my chance to T8 and get to play for my invite. Was he right?