I'm just about to hit the bed and my battery is low so I'll keep this short but the #1 issue against retaliation is the fear of your own rewards, the second one is that countering downvotes does not get you good curation returns.
So how about when we're done downvoting profitable votes and most bid bots have come to terms that they should sell unprofitable votes and since the demand for promotion isn't there right now they'd mainly curate and keep eachother in check, they would co-operate with eachother to split the cost of countering obvious retaliation.
I think we all know which the big accounts are doing this who either got downvoted due to only selfvoting or very closed voting ring/circle. If all ex/hybrid/bid bots that do not have known owners or active posters (but even those who do) would bans together they could easily counter most reported retaliation easily and splitting the voting power needed to do so among eachother and depending on voting power would mean everyone would equally sacrificed a certain amount of daily ROI but the platform and thei own investment would be so much better for it.
Say right now there's maybe 5M SP that's constantly vote-trading, you'd only need to "target" one person in the ring at first and make him acknowledge the EIP and a higher voting RSI, even if they just turned into autovoting curation sniping it's better than the current voting on the same authors constantly. Some would attempt to retaliate but some in their circle would not want to lose their "reputation" to stoop so low.
Those who would would have say 0.5-1.5M SP and if they used all of their VP to only downvote that would be like downvoting with 2M SP max so if all major bid bots worked together that would be like 50M SP sharing the damage of that 2M SP and countering everything. I know @ocdb and the team behind it would surely be up for handling some of it, best part is that their retaliation would also be weak against the very people doing the countering. In most cases this could just mean a 5-10% of CR that would be a bit lower than if you were curation sniping while undoing so much harm and maybe even undo a lot of damage they may have done pre-HF. :)
If @ocdb alone managed to convince an account with 1m SP Early in the HF to give curation a chance and then another similar sized which even retaliated for a while then who knows what we could manage to do working together and while the "abuser" wasn't earning anything in the meantime. I realize some hold keys of inactive accounts and don't even care what happens with the rewards anymore but that's just a cost we have to take upon ourselves to counter until a change happens, the platform needs it and would do much better for it while costing us doing the work less than you might think if we worked together.
Let me know your thoughts! Goodnight. :P