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.