Yes. Clearly bad karma in itself is not enough for trolls and others who frequently get downvoted—there need to be some more tangible effects like comment hiding. This should have been discussed by the authors but I can’t see that they did that (only skim-read the paper, though).
This interesting sentence from the abstract confirms what you say about downvotes being rewarding:
Interestingly, the authors that receive no feedback are most likely to leave a community.
Hence negative feeback is better than being ignored.
Yes. Clearly bad karma in itself is not enough for trolls and others who frequently get downvoted—there need to be some more tangible effects like comment hiding. This should have been discussed by the authors but I can’t see that they did that (only skim-read the paper, though).
This interesting sentence from the abstract confirms what you say about downvotes being rewarding:
Hence negative feeback is better than being ignored.
Or worse, being hellbanned.