Like all things in this decentralized Wild West, a downvote is whatever you want it to be! That being said, the core reasons you list and agree with are the commonly accepted anticipated uses. Throughout the history of the blockchain (and what I’m assuming is happening in your case) there have been individuals who have taken such offense at being downvoted that they go on a crusade to indiscriminately downvote everyone possible in retaliation. Some think that they can thereby expose this “flaw” in the system and get the entire ability to downvote removed from the blockchain. In most cases the mass flagging reaction these folks display clearly illuminates the reason they themselves were downvoted in the first place... they’re assholes! Do your best to pay their votes no mind and take no personal offense.

I personally agree with the legitimate cases for downvotes that you talk about, but I wouldn’t necessarily think ill of someone who used them just on stuff they didn’t enjoy. I wouldn’t ever see myself using the downvote in such a scenario on a creative work, but could be motivated to downvote articles that I felt contained outright misinformation. The intent wouldn’t be to censor, but simply my judgment that I feel the latest “proof” of a flat earth may not be deserving of monetary reward!