your right. it meets a technical definition of censorship. I withdraw my objection based on it not being censorship.
However, even if I accept its "censorship", so what? There is nothing wrong whatsoever with not doing something that pops into your head because you realize other people would not appreciate it, would not understand, or would be offended by it.
There is nothing wrong with that. Yet you make out like its universally wrong. That's ridiculous.
Or are you really suggesting that a high school computer science teacher is showing good judgement if he goes through his porn collection, crops a bunch of the images of various porn actresses and provides those as his sample data set, with attribution. (Because not providing proper attribution is itself academic dishonesty.)
Does he have the right to do it? Sure. Because otherwise censorship right?
But does everyone else have a right to tell him he's an idiot, and refuse to do the assignment, and complain the administration that they feel the assignment is completely inappropriate, and demand he be replaced with a teacher who doesn't make decisions like this. Why yes, they can, because if they couldn't that would be censorship too. And around we go.
Some measure of reasonable self-censorship is part of normal social lubricant. Whether or not you personally feel the image is offensive you are aware that it controversial. If you select it knowingly you provoke controversy. If if you provoke controversy... then own the consequences.
While you have the right to offend. Other people have the right to be offended.