I guess some of those members are simply trying to hunt for merits in that way. In general, new topics are rewarded with more merits than regular posts, so some believe that every big (and not so big) news is a reason to start a new topic. While I am personally opposed to such a practice, there is currently no forum rule prohibiting it. Unless, of course, "No zero or low value posts or threads."
While most of those new hot topics that quite a lot of users start will hardly come off as zero or low value post/thread imo, i do not think the bulk of them are actually hunting for merits per se, cause if you really look at it, more established users who prolly are already up there as Hero or Legendary users are also guilty of this.
If you ask me i'd say it possibly is the desire to share the latest (mostly positive) news about Bitcoin (and sometimes general crypto stuff) to the community, as a result of that, it skips their mind to check if another user prolly beat them to it (seeing the news first and had already posted such), not a big deal anyway, we could always point them to the first topic on the issue and request they lock theirs, which they mostly oblige.
The believe that 'new topics' get more merits is also incorrect in my opinion, what gets merits is constructive posts/threads, if the new topic is constructed properly, with correct facts that is of help here then it gets the merits it deserves, if it does not, and is redundant, then it gets nothing (just being a 'new topic' for the sake of it is not a criteria for merits). On the other hand if regular posts imbibe all of the characteristics i just mentioned then it would get the merits; but all of these still depends on if MS/users who like the post and want to merit it see it.