It's fine, provided it's not a plot hole - i.e. your fantasy setting needs to not have abolished blindness as a realistic malady, which some settings do. E.g. LOTR 100% has blind people, while the Harry Potter universe only has very poor blind people, since solving blindness is as trivial as a polyjuice potion, even if nothing else works (and something more effective is bound to work).
The Netherlands don't have freedom of speech, though, so that's immaterial. The closest thing they have is Article 7, Subarticle 3 in general, which only means they can't legally be compelled to seek prior approval for speech.
Well, the poster is mostly linguistic prescriptivism (defining what words mean). That small caveat at the bottom that words can mean whatever you want them to can't really defeat the entire rest of the poster.
I've never seen "dufus" spelled that way before, it's immediately enticing.- like you hybridized the word with "Rufus".