I guess I would ask why no one seems to want to report it?
If it is truly a nasty attack then it is against our guidelines. You can disagree, you can be sarcastic to a point. But if someone is directly calling others names or being hateful why either ignore it or respond to it? By responding you are just increasing your chances of problems for yourself if someone else reports it. Remember the saying "Don't wrestle with pigs. You just end up in the mud and the pig enjoys it." And "Never have a battle of wits with an unarmed person". . .
Moderators can't and don't read every thread.

They have jobs and families and lives and they do rely on others reporting things to alert them to issues. We don't go scouting the boards looking for nasties. We mostly just join in the conversations of topics we are knowledgeable about or enjoy, and offer help when needed,

just like we did before becoming moderators. If someone is repeatedly nasty nothing can be done if we don't know about it. That is exactly what the dreaded "points" system is designed for. So if they are nasty on one board and get points, then are nasty on another, and another, and another there is a record to see that there is a pattern of unacceptable behavior. Otherwise, you will see the same rude nasty person over and over again.
Just because you can't agree or don't share their viewpoint is not a reason to report.

But if they are being so mean that it makes you go

then let the moderators or webmasters know so they can decide if it needs further attention.