The trouble with that line of thinking is that it runs counter-intuitive to the new diplomatic system. The game very much encourages you to push your relationship all the way up to Allied, both by sending you positive messages to reflect respect rising, and by making agreements better as your relationship improves. Players get the very strong message that it is in their best interests to work hard on getting their respect up to gain and maintain Alliances with as many trading partners as possible.
And yet it's never communicated to the player that they'll be automatically sucked into war if someone DOWs their new ally. Co-operating contains no such clause; the AI doesn't even ask for help anymore (since they can't). There's no reason for a player to expect that Allied status will carry any downside; the game encourages them to think that it will be all positives. Finding out otherwise is a rude awakening, and the reason why in my second playthrough I avoided making allies completely, since I didn't want to lose trading partners. This worked phenomenally well, since I went through the entire game without once being attacked. On Soyuz.
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