passively collect curation rewards

These projects do not collect significant curation rewards.

The curation system is designed to penalize all "passive" curation (on posts with highly-predictable rewards, whether those are always-popular authors, or 'campaign' posts like these) by: a) paying more curation to the earlier curators, forcing people to vote earlier and earlier; and b) returning an increasing share of curation rewards to the pool for votes earlier than 5 minutes. As the competition described in (a) proceeds, more and more of the votes are forced into the before-5-minute zone where curation rewards are returned to the reward pool instead of paid to the voter.

In the case of @burnpost (and I assume @sbdpotato, though I haven't looked carefully), there are always many votes before 5 minutes, and even several dollars of votes before 2 minutes (meaning >60% of the curation rewards which would be earned by these voters are instead returned to the reward pool).

That is to say, the curation reward system is working as designed, even (or especially) for predictable payouts that don't require a lot of curation effort. It offers voters a choice between low rewards for low effort or higher rewards for higher effort. It probably isn't feasible to have a system that pays no rewards for low effort for two reasons: 1) "low" or even "no" effort is not knowable by the blockchain except by observing votes, and to measure such a thing requires a graduated scale; and 2) reducing curation rewards too much, even for low effort votes, encourages vote-selling, which is far worse for curation overall.

In fact, people voting on @burnpost, @sbdpotato or even other 'passive curation' (such as voting on consistent high-payout authors) could and often would do better by picking some 5+ minute old unvoted content at random.