If your upvote is small (less than 0.02 steem) then it never pays out curation rewards.

If your upvote never pays out curation rewards, then you can't be accused of "vote farming", because you're not taking any "money" from the reward-pool-pie.

These vigilante groups, steemcleaners and steemflagrewards, ONLY care about "protecting" their precious-magical-reward-pool-pie.

I've spent an enormous amount of time trying to figure out why high-powered-accounts would spend so much time and effort encouraging downvoters and hunting down "low-effort-exploitative-content" and it turns out, the answer is right in their discord channel,

"Hey spam fighting neighbors! @ everyone One of our fellow spam fighting teammates came up with a great idea. # abuse-fighting-tools is your sneak peak at some of the favorite ways to discover and or smash these pesky reward pool abusers."

Strangely enough, the most consistent TOP-EARNER (total steem rewards awarded per previous 30 days) is steemcleaners. The more downvotes people make, the bigger slice of the reward-pool-pie gets shoveled into the mouths of the TOP-EARNERS (that's how the reward-curve is designed, 80% of the pool goes to the top 20% of TOP-EARNERS).

So, as long as you don't cut into their private reward pool, they'll most likely focus their attention on more profitable targets.