No, I don't. IRON has shown in the past that they honored their treaties. They (according to you) were known for being a solid partner. For me, they'd still be one. I can't deny they didn't honor their treaty with NG, but they had a good reason for it (See iamthey). They chose friendship over paper, I can't blame them for that. In fact their decision was independent. They didn't follow the upcoming public pressure, but chose their friends instead.
The only thing we can blame them for, is not canceling the treaty earlier. Then again, considering the communication between both parties, it could have been expected. That lightens the "guilt".
I am sure people can understand this.
That would have made the situation legally "acceptable". However it's not that when people cancel treaties prior a war, they don't know what the future coalitions will look like. So in both scenarios they'd have caused bad blood.