I think this was a good call. I think we would do well to continue building our defensive capabilities to defend ourselves and the capital as well as offensive to be a force to contend with if challenged.
Indeed I think we already are such a force. Maybe we wouldn't win in an all out war with dawnwalker but their victory would be a pyrrhic one.
This was likely an accident but perhaps MrY wouldn't repay more because he isn't able. We all have to compete and his score isn't rising as fast as some of our members. With fewer resources and no buildings to upgrade he has to increase with troops. Not to mention that his attack cost him dearly thanks to a stuff defense he was facing. Think about it this way: HE used a strategic shift to get away from US.
In summary we can let this one go but to remember that if we weren't strong this might have been a one sided war. We are strong and will be stronger. We are reasonable but not pushovers.