If we can agree that "demerit" is "apuññaṁ", then the Buddha tells us:
AN2.134:1.1: “Dvīhi, bhikkhave, dhammehi samannāgato bālo abyatto asappuriso khataṁ upahataṁ attānaṁ pariharati, sāvajjo ca hoti sānuvajjo ca viññūnaṁ, bahuñca apuññaṁ pasavati.
AN2.134:1.1: “When a foolish, incompetent bad person has two qualities they keep themselves broken and damaged. They deserve to be blamed and criticized by sensible people, and they make much bad karma.
Sharing such demerit could then be understood as:
AN2.134:1.3: Without examining or scrutinizing, they praise those deserving of criticism
AN2.134:1.4: and they criticize those deserving of praise.
The Buddha continues and says this about merit:
AN2.134:2.3: After examining and scrutinizing, they criticize those deserving of criticism
AN2.134:2.4: and they praise those deserving of praise.
AN2.134:2.5: When an astute, competent good person has these two qualities they keep themselves healthy and whole. They don’t deserve to be blamed and criticized by sensible people, and they make much merit.”
However, until one is free of delusion, it may perhaps be best to pay proper attention and say little until wisdom is gained. For example, praising organized crime bosses for their local generosity may also support their ongoing criminal ventures. And it's usually fatal to criticize a crime boss.
MN8:16.1: Truly, Cunda, if you’re sinking down in the mud you can’t pull out someone else who is also sinking down in the mud.
MN8:16.2: But if you’re not sinking down in the mud you can pull out someone else who is sinking down in the mud.
It's actually quite hard to escape demerit by focusing on demerit. It's much easier to escape demerit by focusing on merit. That's why it is critical to practice and follow Buddhist ethics.
MN8:12.7: ‘Others will speak divisively, but here we will not speak divisively.’
MN8:12.8: ‘Others will speak harshly, but here we will not speak harshly.’
MN8:12.9: ‘Others will talk nonsense, but here we will not talk nonsense.’
(...omitted for brevity...)
(Now(submitted by Anonymous)
"Now I have to think whether sharing the hunts of Robin Hoods would fall under share of merits or demerits to make the circle of escape closed within)within" --Anonymous
Exactly. From a Buddhist point of view, stealing from the rich is still stealing.