I notice that also, especially after one member of a Russian local board posted here about his achievement to get from 0 to 1000 merits. I have to admit that he was completely unknown to me and I didn't notice him anywhere in the forum, and only when I look at his merit history everything became clear to me. I also do not consider this an abuse of merit, but rather that the local board has a sufficient number of merit sources active in its local boards.
I think the OP is actually from the perspective of the ordinary observer concluded where the most merit circulates, but he did not realize that in most cases it did not matter where you post (with the exception of altcoins boards), but what you post. I don't blame him too much, he'll learn over time.
This was likely an attempt to gain a little merit by sharing their observations, but again they're a new user, and I know for a fact that my posts back when I was a newbie wasn't that high of quality, so I think it would be a little harsh to jump to the conclusion that this user will not be a quality user of the forum in the future, and thus the benefit of the doubt should be given when it comes to ignoring them. It was only from learning about the forum, Bitcoin, and maturing as an adult that I started to improve the quality of my posts. I think its quite well documented that humans are bad at spotting connections, and patterns. An example, of this which I'll admit is a little off topic, but still is a good way of looking at it; is if you have a bad day because you broke a mirror, and then had bad luck you would associate bad luck with the breaking of the mirror. Although, of course this is an extreme example, but gets the point across. Of course, breaking a mirror doesn't have any association with the outcome of your day usually, and is just being superstitious. I guess what I'm trying to relate this to is just because there is more merit within a certain section doesn't mean that if you post there you'll get more merit. Its in fact the quality of the your posts, however certain sections as pointed out by a few people draw in better quality users.
Development & Technical discussion is a prime example of this. Spammers are put off by posting in this section mainly because it actually requires some intelligence, and knowledge of Bitcoin to participate in this section of the forum. Something which a lot of spammers tend to avoid not because they're inherently unintelligent, but because they don't want to think, and want to post as much as possible with as little effort as possible. Signature campaign users usually flock to the easy to discuss options, and this is a common problem for the campaign managers when they hire someone, because for the majority of users will have a change of mindset as soon as you introduce money into the equation. Anyway, to prevent me going on more of a tangent; my point is that certain sections of the forum invite better quality posters, and the merit spend on that section is a result of this rather than the actual section itself. If a low quality user was to post in these high spend sections they would not be anymore likely to receive merit than other sections, because it is highly dependent on the motive, and quality of the post. There are some mild exceptions like local sections, and the altcoin section.
That's really good because there are many newbies here whose activity already crossed the SR members but don't know about merits. Even they don't care about it 
