If we're doing the virtue ethical banning, then as long as we agree that the people in question deserved a ban, the specific reasons given for the ban aren't very important.
Yes, they are. They set the percedent for which other users get banned.
I think you misunderstand virtue-ethical banning. It's not about what you say, it's about who you are. "Precedents" are a deontological idea.
I've gotten sufficient evidence from support that voiceofra has been doing retributive downvoting. I've banned them without prior notice because I'm not giving them more chances to downvote.
I'm thinking of something like not letting anyone give more than 5 downvotes/week for content which is more than a month old. The numbers and the time period are tentative-- this isn't my ideal rule. This is probably technically possible. However, my impression is that highly specific rules like that are an invitation to gaming the rules.
I would rather just make spiteful down-voting impossible (or maybe make it expensive) rather than trying to find out who's doing it. Admittedly, putting up barriers to downvoting for past comments doesn't solve the problem of people who down-vote everything, but at least people who downvote current material are easier to notice.
Any thoughts about technical solutions to excessive down-voting of past material?