ALSO PRETENDED TO SURRENDER AND TRIED TO RAM HER 
Isn't it a war crime to pretend to surrender?
I'm not even sure it is today and who knows what kind of rules the UEF has down the road. I'm pretty sure they aren't using the 100% same genf convention we have in place today.
Besides the GTVA bombarded civilian population centers with nuklear weapons and blew up plenty of civilian ships and stations. Compared to all that a pretended surrender is a very minor thing.
If they would have succeded (probably meaning taking out the Imperieuse beams), Byrne would probably have raged a bit about such dishonorable tactics, but that's pretty much the worst they would have incured (their comrades anyway, since they would have been dead from the ramming or course), since they were not under Byrnes command. The other two Admirals would probably have given them postumous promotions and medals.