I contributed to the demise of my M in part b/c I love to debate and play devil's advocate, and my X did NOT appreciate that. It would have been better to do the whole quiet active listening thing, letting her merely vent.
When a woman is in full blown vent mode - the ONLY thing that works is sympathetic empathetic noises/words. I know in my case - I am not even listening. My blood pressure is through the roof and it affects my brain's ability to even think rationally. My brain interprets any disagreement with respect to The Vent as "you don't support me." Expressing an opinion - especially one contrary to The Vent and INTERRUPTING the venting process - well the man clearly has a death wish! LOL!
Sorry there is no rational answer for this one. I can only share my own out of brain experience when I go into vent mode.
In my case, I am usually approachable to rationally discuss/debate the issue roughly 24 hours later.