The neutral simplified version:

KotakuInAction had strict moderation. Partially to try to avoid getting banned from reddit and partially to try and keep things on topic. The mods at KotakuInAction wants to keep the movement focused on video games and not the greater culture war at large. KotakuInAction2 went with lighter moderation, while still having a focus on gaming also discusses the wider cultural war as well.

KIA1 probably overmoderated and a lot of relevant stuff wasn't allowed, but KIA2 is probably a bit too unfocused and a little spammy at times.

KiA mods wanted to keep the sub hyper focused on gaming and kept introducing rules to keep the focus narrow. Eventually they held a vote on one of the rules. The vote went the opposite way the mods wanted so they ignored the vote and brought in the rule that they wanted to in the first place and it ended up getting rid of every second post submitted. A sub was set up to try and mediate the difference between the community and the mods but the mods did not participate and ignored everything that the users raised (hats of to TheHat and AdamRises for making a big effort despite it being futile). That fell apart when one of the mods entered in there and only spent their time their insulting AoV before leaving.

KiA2 formed in protest. KiA increasingly seemed to attempt to narrow the scope whereas KiA2 accepted that GG is simply one field of battle in the wider culture war. The mods on KiA became more and more antagonistic against the people unhappy with the backflip and disregard of the vote, unhappy with the heavy handed moderation and attitude of many of the mods. The mods on KiA started banning longtime contributors and eventually kicked one of the only mods that was trying to keep moderating with the original spirit of the sub.

KiA2 became more and more active over this time. The mods on KiA doubled down and started calling users of KiA2 all the standard SJW insults (nazi, white supremacist etc.). The subs sort of entered into a bit of a stalemate and did their own thing (though some of the mods on KiA still felt the need to throw shade every now and then).

KiA is still going ok and KiA2 is coming on strong a getting good growth and activity.

KiA is trying to keep an image of being politically neutral whereas KiA2 is openly anti leftist at the moment because the issues with media are all stemming from leftism at the moment.