While anyone is entitled to do or say anything they want, and there is no rule against "campaigning" for a Hugo Award (how could you possibly enforce such a rule?), I think there is a considerable difference between saying, "These are the works I published last year, and if you liked them and are eligible to vote, I hope you'll consider them on your ballot" and "Here's my slate of nominees. Won't it make lots of people angry if you all go out and nominate them?"
I consider "I published this stuff last year" messages to be aides-mémoire, not campaigning. I work with the other members of the Bay Area Science Fiction Society to discuss what we read/saw last year each February/March and to publish a list of our recommendations for others that we publish on hugo_recommend, and that often helps me remember things that I read/saw and liked but forgot, particularly things published early in the eligibility year. I don't consider that the same as publishing nominating slates whose motivations seem mostly negative to me.
Again, there's no rule against negative campaigning. You can say anything you want. I just consider negative campaigning to be personally distasteful, that's all. I'm not advocating rules changes or Strong Administrators who will make sure the Right People win. All of you people who want Strong Men Running Things should be very careful about what happens when the Strong Man decides against you. And that goes for everyone, regardless of your position on the political horseshoe.
There were something close to 10,000 people eligible to nominate this year, and more people nominated this year than cast final ballots last year, blowing the previous record for nominating ballots cast out of the water. I think the increase in interest in the Awards and increasing number of members of WSFS who have decided to actually cast their ballots is a good thing in general and makes most it harder for small, hard-core blocs of voters to dominate the results. When the Hugo Awards get written up in USA Today (albeit in an opinion piece I did not personally care for), perhaps it shows that the Award matters, despite those people loudly declaring the irrelevance of all awards in general and the Hugo Awards in particular.
Note: You do not need my permission to link to anything I write in a public post on LiveJournal. If I want to keep something among my friends and out of the hands of search engines, I'll friends-lock it. That's one of the reasons I stay with LiveJournal, aside from having purchased a life membership the last time they were available.