Does not sound like merit abuse to me. Sounds like reasonable discretion in which not everyone is going to necessarily agree about how to exercise such discretion. In other words, there is a range of reasonableness that is acceptable, and each of us will likely have different balances in what we consider to be reasonable.. I doubt very many folks would consider that withholding merits in those circumstances to be abusive - even though you have reached that conclusion.. which might even put your reasonableness in to question that you would label some kind of practice like that which seems to be reasonable discretion to be abusive.
For the merit system to work entirely, those who are part of it should help in distributing those merits, not just receive them and hoard them forever. That's how I see it. Everyone decides for themselves. Are you in or are you out? I have no problem with user X not meriting other people. We can still talk, joke, be serious, even trade with each other or run a business. None of that requires me to reward you with a unit that you don't care about.
If the majority of merit receivers only hoarded their merits, it would be a failed experiment, and the only way to receive merits would be from merit sources. Right now you can get merited from both merit sources and regular members who aren't and I would like to keep it that way by rewarding those who understand that. The merit economy works because people make it work. If everyone stopped caring then we can just forget about it.
I don't disagree with you, but in the whole scheme of things, there are not very many merit hoarders.. so in that sense, it probably does not matter that much if you send merits to ONLY the hoarders because there are plenty of folks who still give out smerits.. Furthermore, the opposite is true in regards to you having a strict policy that you will ONLY give smerits to those who have previously sent out smerits (the non-hoarders), and I know that even you are not taking that extreme of a smerit distribution position, but even if you did take that extreme of a position in either direction, to me it it would not seem to rise to the level of "abusive" for you to have strict standards on that point.. even more strict than your current stated views.
To me, it just seems like the wrong word to suggest that your having and practicing strict policies regarding not sending smerits to hoarders would be "abusive" absent some kind of further evidence that you had some bad motives or that you were targeting a certain kind of member for some other bad reason... your targeting hoarders does not seem abusive.. even if you are actually doing it to the extreme including if you refuse to give merits to no longer active members because of your strict rule recognizing that they would not be sending smerits out.
Absent some additional evidence the targeting and discriminating against merit hoarders or even the targeting of non-hoarders (to take the opposite extreme) does not seem to rise to the level of my idea of what would be "abusive," even if it were to be more extreme than your actual policy/practice in either direction.... but I could see that the targeting of non-hoarders might have a better chance of rising to the level of abusive rather than the targeting of hoarders for the reasons that you stated about facilitating the merit system as it currently exists..
(sorry I might have made my position even more confusing when I am trying to suggest that there is a wide range of reasonableness that merit sources might have in exercising their discretion by taking extremes on both sides).