I guess I'll reply to all of your nodes here.

Regarding "forced empathy", I wonder if some other system could be worked out instead such as not counting the vote if it would cause an XP loss [to the person doing the voting]? Perhaps this could even be configurable (so those who are fine with losing some XP can do so while those who do not like the idea can avoid it).

If the prospect of losing 1 XP before one notices that they've cast a long string of down-votes is unacceptable to somebody, then they are a huge hypocrite for casting so many down-votes subtracting so much from the XP of other monk(s). So if losing XP is so abhorrent to somebody, then they need to stop imposing that terrible fate upon others. Period.

Anyway, I'm just throwing some ideas out because I think sending negative feedback for positive actions will discourage the positive actions.

Oh, I'm completely fine with discouraging long strings of down-voting. And long strings of down-voting are hardly ever a "positive action". Even when it isn't abuse or verging on abuse, it is most likely at the very best a "mixed blessing".

I'm curious because in the OP you claim these are minor changes yet it seems like at least in the scenario above your changes are anything but minor.

How many times has that (systematic plaigerism) happened? Yes, I consider that scenario to be an extremely minor part of voting/XP at PerlMonks.

I assume you have read that node of mine that you keep linking to. I've re-read it and I don't see where I encouraged massive downvoting of all past nodes because the XP loss will solve the problem. The only sentence that I can see even pointing in that direction is "If you are concerned about copyrights, then contact the alleged owner and/or the alleged copier (the two parties that have both the power and responsibility to do something about it)". I don't consider "down-voting" to qualify as "contacting".

And my node had very little to do with plagiarism (it was about copyright and also about how copyright likely didn't matter much in that plagiarism incident).

I think it makes good sense to raise awareness of the repeated behavior. I think it makes good sense to mark many of the plagiarized nodes with indications of where they were copied from and even pointing to a node about the larger pattern of behavior (by replying to them and by asking the author to fess up in updates). I don't think it makes sense to consider the old nodes. I actually don't think that systematically downvoting the old nodes is required or even much of a "solution". Given the rules at the time, it was fairly inevitable and so the vigilanteism saved the gods from making a ruling about punishment, not directly for the plaigerism but to compensate for the ill-gotten XP from gaming the system via systematic plaigerism.

So I guess your points all really just go back to this one incident. Which means still allowing (and not even discouraging) systematic vigilanteism in case something like this happens again. That would require allowing the current abusive downvoting of all old nodes of a single author which means just undoing the majority of the changes. But, no, I don't think we should list "vigilanteism" as "amongst our weaponry that includes such diverse elements as...".

Had this incident come to light in the future, I suspect the gods will have been forced to get involved not because imposing an XP penalty would really solve much, but because not doing so would seem unfair to some who "played by the rules". (time travel makes for complex tenses)