Anonymity is definitely part of the issue, and most likely one of the roots of the community. Gaming communities nowadays are toxic in general, be it because “skilled” players talk down to people who play “casually” - while games in general should be just that, games. Admittedly, I do get annoyed at people who are deliberately trolling, or who are simply refusing to do their job as well as they can in an MMO, especially if everybody else’s progress depends on it. That applies to daily dungeons where you are highly dependent on everybody’s readiness to help as well as to endgame raiding where any mistake from any person, or simple lack of understanding of the fight or task at hand will lead to a wipe and waste of time for others.
But be it dungeons in ToS or raids in FFXIV, people rarely ever speak up against those who act offensively against others. Racism is only part of what can happen during those times.
And, as you put it, maybe we veterans didn’t react quickly enough, and especially openly enough, in the past, to prevent the situation we have now - people talking down upon others due to their nationality, lack of experience, or even disabilities like color blindness due to which they cannot perform as well as we want them to.
Anybody who is willing and ready to help will act against that development, but most people are too focused on their own gain or have simply stopped caring thanks to too many situations where they tried to stand up for others and became target to the offensive actions themselves. It’s never easy to take a stand against things like the open racism in shout channel, especially with the age gap being as great as it is, where half the 15-year-olds will make fun of you and everybody who could take you seriously has stopped reading the spam long ago. That applies to this forum, to dungeon runs, and to any other occurences of those situations, just as well.