I thought it was decided to NOT take action against merit abuse cases anymore, to just let them be and wait for the merit airdrop to run out..
DT members like actmyname do tag merit abusers, but only in obvious cases where there's little doubt about what's going on. I've seen Vod tag people as well.
In general, though, you are correct that merit abusers don't get tagged. It's a very gray area and DT action has been less consistent than, say, loan scammers or bounty cheaters and that's because of the inherent uncertainty as to what people consider good posts and how much merit to give out. Theymos has also suggested that suspected merit abusers shouldn't be tagged, that it'll all work out in the end--and that's why I haven't been leaving negs for people.
Some members have probably ranked up when they shouldn't have, because they're shitposters, but overall it's still MUCH harder for them to do so. That's progress.
People who abuse merits forgets that they can only use it once and when it gets used up, its either to conform to the rule of the forum on getting merit legitimately, or they are stuck in one position and because opening a new account won't come with merits, that won't be an option to consider which is why I agree with this submission entirely. The earlier we start following the rules the better for everyone. Most times people who are of the lower ranks always believe they are subject of targets when some rules are made rather its meant for the betterment of everybody.