Since Hardfork 21 a couple of weeks ago we all have some free downvotes to use. You can effectively downvote 2.5 times at 100% each day if you want it to recharge by the next day. This does not eat into your upvoting potential as it used to, so you do not miss out on curation rewards. The outcome has been that lots of big accounts have been downvoting posts that buy excessive votes for their posts. Here is a prime example. We need some whales and orcas to get in there before it pays out as this reward is for a weather map and a few lines saying there is a typhoon coming (in Korean).
There are lots more people doing this still. You may say why should you do anything? The reason is that these people are reducing what you can earn on Steem as they eat into the daily reward pool.
If you are looking for something to downvote then check out the posts by @dmacs that give examples and reasons. @steemflagrewards also lists posts that their team have found and already downvoted. If you delegate to @curangel you can nominate posts for them to downvote.
Of course there is some risk of retaliation, but a lot of these people hold very little SP as they power it down to buy more votes.
There will be posts that deserve to be seen, but it should not be necessary to buy multiple votes for that. In any case a lot of these posts have little or no interaction, so it is not working as promotion. It is pure greed. Rewards are intended to be distributed by users, not bots. Just because the freedom of Steem allows bots to operate does not mean we have to tolerate this selfish behaviour.
Do what you can for Steem. Every cent counts.