If every post is flagged to zero, it won't be long until that person reputation is also zero... Or even negative. From that point their posts will be hidden from every frontend, and even if by some kind of fluke you find their post the images won't show... And that person needs to host the images outside of hive because the Blockchain won't allow you to upload images if your reputation is negative.
So, yes, constantly flagging someone's posts is censorship, no matter how many excuses people find to claim otherwise.
Not really true. The reputation goes down only if the vote is stronger than the upvotes. If the downvote is only worth the upvotes, and just negates them, it shouldn't affect reputation. But if the downvote is double the upvotes, it will soon start affecting reputation.
If someone's reputation is below 25, they've likely done something dubious, or even actually illegal, like for instance copyright infringement, plagiarizing, harmful hoaxes, spamming, tagspamming, or handlespamming.
You are okay with spam or hoaxes getting "censored", right?