Why so much rage? Losing is part of becoming a better player, and ultimately winning. I get mad with a game when it's boring and the same every time, and the AI doesn't put up a fight.
Rage is just part of the fun and generally makes me keep going instead of quit. For example, the first time I encountered Neinzul Cockroaches with translocation, they made me angry which is why I enjoyed destroying them. So it's not ragequitting all the time, it's a reaction almost as if the enemy was real and I just wanted to obliterate them. That particular game where I quit, I quit because I had only my half-dead homeworld left and couldn't secure any other planets because of a lack of energy to power my fleet, which was already woefully outclassed.
The AI is awesome because it can make you rage, which is something I have never encountered before. For example, Starcraft 2 has a very predictable AI: it never rushes you or changes its strategy, whereas AI war is built around a computer opponent that isn't just a cakewalk.
Latest game I have turned the difficulty down and... it masses 400 ships each on 3 worlds near some of my key borders, so I decide to swing by one of those garrisons after I take an ARS, which results in 300 losses for me and a 2-pronged counter-attack that destroys all of my science labs before I know what happened. A couple hours have passed in that campaign and now the AI is tempting me with 600-700 ships on another border world, just waiting for my fleet to wander too far away or attack out of fear and trigger my doom.
I think it's great that the AI can exploit human emotions since it gives them a strategic and tactical advantage when I focus on the thing that makes me mad instead of the critical objectives.