A resounding 'No, it is not!'
You might be a bit surprised, what with all the claims of persecution and prejudice constantly spewing from creationist sources. The truth of the matter is that creationism is not banned from being discussed or even taught in school. What is true is that since creationism is not science, it cannot be taught in science class as if it is science. At least not in public schools without violating Federal laws AND it shouldn't be taught in private schools without violating common sense. There's a world of difference between being banned and not being taught as science.
So when and where would it be appropriate to discuss creationism? Let's approach this from a different angle. Does anyone remember taking a Chemistry class? Did you discuss alchemy? More than likely, but it wasn't taught as if it was chemistry, was it? I don't believe so. It was taught in a much more historical context in tracing the history of the science we commonly refer to as chemistry today. Right? When you discussed scientific methodology, it probably came up again since alchemists developed many laboratory techniques, theory, terminology, and experimental methodology, some of which we still use today. So right there in the science classroom, you are legally and perfectly correct in bring up the topic of alchemy. But you cannot teach alchemy as if it were science -- why? Because it's not science as we know it today, but as odd as it might sound, it is still practiced today -- although the names have changed to things like 'new age medicine' and 'homeopathy', it involves many of the principles used by alchemists throughout history.
How about 'Flat-Earth'? Did you also discuss this as a concept? Possibly in History class, maybe in Geography. Was it taught as if it were science? Of course not. But the historical perspective of what many people believed to be true fit's into the discussion both from a historical perspective and the geographic. These perspectives are actually still believed by some people today. There is a link to the 'Flat Earth Society' website, whose stated mission is:
" . . . to promote and initiate discussion of Flat Earth theory as well as archive Flat Earth literature. Our forums act as a venue to encourage free thinking and debate."
I do love the phrase 'encourage free thinking and debate'. Sounds like a common enough cry from many Creationists when they try and insert Creationism into the science classroom. How often do we hear plays on the concept of 'We're not anti-science, we just want there to encourage free thinking and debate on evolution, since it's only a theory after all.'
So why do creationists claim to be banned from school? It's nothing more than an emotional argument that appeals to our sense of fairness, to our outrage that ideas aren't being freely expressed in our schools. It even appeals to our own religious notions, even if we disagree with theirs. But the reality is they are not banned from the classroom. They are simply placed within a context appropriate for the venue. When it comes to science, the reality is that creationism is not science and no matter what lab coat you dress it up in, be it Creation Science or Intelligent Design, it is not nor should it be taught as if it were actual science.
Unlike creationism, science never fully closes a door. It is within the realm of possibility that someone may actually offer evidential support for some aspect of creationism at some time in the future. I cannot say what it might be, or when it might happen. But the possibility always exists. Science, unlike religion, always leaves the possibility there, even if the probability is minuscule. That's not an opening for religion, but it's an opening for religion proponents to provide the support that would take them from the supernatural to the natural. That's how science works, we never completely dismiss an idea, but the proponents have to play on the same playing field as scientists. Until they offer proper and validated scientific support then creationism belongs with alchemy, flat-earth, tarot cards and the like. Not banned, never banned, but not taught as if it was an equal part of the curriculum.
So when a Creationist or Creationism website makes claims for being banned, know the truth. They aren't banned, they just aren't given validity. Validity is earned, not just given based on who whines the loudest. You might also notice that while alchemy, flat-earth, and even astrology can be discussed, no one is crying to teach them as alternatives and allowing students to make up their own minds, yet you hear that often from creationists. Wonder why that is?