I get that too. But I don't see why a standing alliance in your mind is the only reason to get involved into someone else's business. Sometimes you're not allied with either side but you're pursuing your own interests. In this instance - making sure Shadowdale does not get too powerful and dominate the region. I think it's legit. I also liked that they coordinated a pincer sneak attack instead of just mass-declaring/dogpiling on SD.
It just seems to me that controlling how alliances are shaped and then absolutely confining all group conflict strictly along the alliances lines will lead to stagnation. We have war island for that sort of gameplay, where politics are decided by game mechanics. I don't play on war island and I don't want to.
I don't know, maybe you did not enjoy that aspect of the game when you actively played BM. But you can't deny it's important for many here.
While there may be cases that fit what you are describing here, this was not one of those.
We have messages from well before the actual intervention with the three realms talking to and about each other as if they were allied, and the whole thing was very deliberately coordinated.
