Honestly I would react the same way if a game I was currently playing or was looking to play next after getting through the three or four other 50 fucking hour games that this year is jamming down my throat was about to be spoiled in one or way or another. You can't hold people accountable for having not beaten a game yet that came out a month ago. We aren't talking about Final Fantasy 6, this isn't a case of "well the game is so old WHAT ARE YA WAITIN FOR HUUUUHHHH?!" this is a case of not enough time, too many damn great games, and great games with great plots. It isn't their job to be spoiled, it's their job to entertain us and while I understand that having members walk out of a room to avoid spoilers might be detrimental to someone's enjoyment, what would they have contributed to that discussion anyway having not played to that point? If two people who played the game were going to be the main contributors to that conversation then what's the difference if those not hoping to have moments of the game ruined on them step out for a second?
There are certainly things that some consider spoilers that are not spoilers, moments where the cover ears and shout LA LA LA comes to be an overreaction, and I am guilty of that too in this very thread when it comes to Persona, but making it sound like spoiler culture has gotten out of hand and shaming people for avoiding them is too much too. We live in a world where someone will go in the comments for a fucking shampoo or something and ruin The Force Awakens, or make a Twitter spam bot that LITERALLY TWEETS YOU PERSONA SPOILERS, or PM random people Fallout spoilers or whatever. People are going out of their way to troll the living hell out of people in this regard so it's become even more annoying for those trying to avoid them. If you aren't sensitive to spoilers, power to you. There are a lot to games other than story and knowing story elements don't exclusively ruin a game but they're still a part of a game, especially games like Persona or Nier that look to tell fantastic stories. It's the journey not the destination does not apply when the tension of not knowing and discovery is part of that journey.
Call it overreaction, call it what you want, but there is nothing wrong with dodging spoilers on air for something you care about.