I find the attitude of moral superiority some people have on FAF is pretty toxic in itself. There is no objectively right or wrong way to communicate and act. FtX and Biass seem to get more done than most people, so maybe their way of acting is actually superior. Playing god and saying these people's way of acting is wrong because you said so seems worse to me than the people who act "toxic" sometimes.
As far as player retention goes you seem to ignore that FAF player retention numbers are good compared to other games. Every game will lose most of its new players, that isn't a good excuse to not try and find new players. What percentage of player retention do you aim to achieve before beginning external promotions? Assuming people mainly leave due to toxicity also seems like a big leap. You made a thread on the forums, which only active community members read, and a few of them said they would have quit due to toxicity. They didn't quit due to toxicity though, because they are still here and participating in the community. Seems like survivor bias to me.