How long have you been playing Rohan. And you haven't figured out that MR is a fact of Rohan life yet?

Y'know if your guildmates are abusing MR, kick their lame a$$es out of the guild. Simple solution. However MR does exist to allow guilds to freely war with each other without penalties associated with 'murder'. If a guild misuses MR to go on rpk sprees in akhma then KOS their lame a$$es too. Your guild too weak to do that, then make a stronger guild then KOS their lame a$$es.

It is all connected and part of the dynamics of Rohan. Don't expect it to go away. It won't. Don't like it there are games with more regulated pvp out there.