Quite often I imagine many choose not say anything, and things should be said. It is certainly not going to change the person who posted that. I doubt one can "grow" from that low of a level to become much, but it highlights an important topic for everyone else. I will certainly be more mindful and try to be more inclusive when talking to groups (I am guilty of using "guys" often even in mixed groups).
At the same time one can generalize this and ask "how should we deal with trolls in online communities?". Gross jokes, racist comments, the worst one can imagine pop up often in anonymous online communities. The joke about how the language is now "famous" was perhaps not a good joke but there is dose of truth. The language is more visible. One certainly could have logged into the channel even if it had 2 people in it and proceeded to make offensive comments, but the chance of that was just lower. Now it is higher. There will be worse comments seen as well. Sadly it is just a fact of human nature and interaction online.
Now to dig at it a little deeper. I wonder if the disgust and shock was aimed equally at the silent majority, who I suspect, the author feels should have condemned the insult publicly. Sometimes things are written between the lines. The expectation is that one a member of a group is attack I would want to be defended by other members or at least get private words of support from them. And that would make sense except that the practical means of dealing with a troll is to ban and ignore. Condemning things publicly, calling them names back, insulting, even openly discussing it while they are around, just fuels the fire for them. They mission is accomplished then. So everyone ignores them. But to the person who was attacked, it seems like the tacit majority agrees with the attacker or at least doesn't feel the attack warrants words of support.