Inappropriate censorship by Duobot
Duobot wouldn't let me upload an article on a frozen prehistoric mummy that was found in the Alps and that was a major archeological discovery (https://pt.wikipedia.org/wiki/Ötzi, English). It complained that Duobot thought it was not appropriate for all ages.
After some experimentation, I found that an offending sentence was this one: Ao morrer, trajava vestimentas que o protegiam do frio, com três camadas de roupas feitas de pele de veado e de cabra, além de uma capa forrada de fibra da casca da tília, árvore tipica no hemisfério norte.
This means approximately this: "When he died, he was wearing clothing that protected him from the cold, with three layers of dearskin and goatskin, in addition to a coat lined with bark fibers of tilia, a common tree in the northern hemisphere."
Any ideas about why it would flag this sentence?
Ok, here is another ridiculous example. A friend had had trouble uploading a Spanish Wikipedia page on Miguel Servet. After some experimentation, I narrowed it down to the offending word, "estaca," ("stick"), a very common Spanish word that is occasionally used in some countries as a slang for a part of the male anatomy. (I would just spell out the P-word, but I don't want this post to get censored.)
Even when I created a one-word Wikipedia page that consisted only of the word "estaca," Duolingo rejected it as unsuitable for some ages. I had spent so long trying to get it uploaded that I removed the two instances of the word from the actual Wikipedia page just long enough to upload it to Duolingo, then restored them a few seconds later. (Modifying the article in a scratch area of Wikipedia assigns your Wikipedia user name as the title of the article in Duolingo.)
This is obviously not a reasonable workaround.
This kind of filter just does not work. In Portuguese, "rapariga", that means girl, may in some places mean prostitute; "bicha" in Portugal means line, queue, in Brazil means male homossexual. The same means "florzinha", that is otherwise little flower. There are lots of words which meanings changes completely, as "sapatão", big shoe, that mwy mean female homossexual. A machine cannot make these meanings, as far human language is quite complicated. The best policy is to allow readers to flag unappropriate material and some volonteers to decide if the text should be delected or even if the author should be expelled of the community.