Some of them may take advantage of the opportunity to get merit, but some of them also sincerely want to choose. I'm not entirely sure what the goal is, but merit is one of the main draws of most spammers during voting.
I probably wouldn't blame them completely but maybe some merit source would also really like to appreciate it even if some of them aren't great posters so far. But I can think of something positive about it and one of them is introducing merit to spammers who might later change their behavior when they realize that merit is a rank up requirement.
I think most of the earlier votes were genuine, although I'm definitely seeing a pattern of users popping up, and voting for those that are rewarding votes with merit. That's probably not enough evidence to be absolutely sure that was their sole motivate, but I think it has definitely played a part in some of the votes. Like I suggested before, if this voting event is going to become a annual thing for years to come, them maybe the admin team could prevent merits being sent in the thread to prevent abuse. Although, I'm not sure it's a massive problem in the grand scheme of things, it would just be a shame to see a community event be ruined by it, as I do believe that message behind the event i.e recognising those that contribute to the forum in one way or another, is a good one.