This can be easily avoided if people don't give merit only to those that give them vote and ignore the rest. I know that some people like to use merit as a "thank you", but IMHO in these situations it's best to avoid that practice as some will vote only to scoop couple of merits. I remember last time we had some members who were so lazy that they just copy/pasted other people's votes. [...] I am having the same issue. For now I just left some categories blank and will eventually fill them up when/if I figure out who is the most deserving. Or maybe I am taking this too seriously. 
I remember this heated discussion... so I'm of the opinion that only people who are not on my ignore list deserve ratings (in the context of how I feel when a person has spent 5-10 minutes making a conscious choice). Btw, there is nothing wrong with leaving a couple of empty graphs, to me it just means that the person has a slightly narrower range of interests than others ... after all you have a month or so to edit your post. 