Looks like a classic case of merit sales to me.
• User A has lots of farmed accounts and advertised merits for sale on telegram, discord or wherever else they do,
• When they get a buyer, they pick one of their accounts to send the merit through,
• They know this would have a negative impact on the receiver, but do not care much for that.

Good catch op. These users would eventually run out of merits to send an the system would purge them out.