Just my two cents coming up here, I'm procrastinating
This probably takes us some way off-topic, but I still don't see the problem of people learning whatever they want to.
There is a large difference between learning whatever you want to and being taught by a person of authority whatever
they want to teach you. As mentioned before, that should be chosen by a consensus among those working in the field.
Sure, I don't agree with creationism, but to write it all off as nonsense isn't really fair either. There are a few intelligent people propagating the ideas, capable of mounting something of a defense.
And those people - and there are undoubtedly some intelligent ones - are also very strongly religious. They make their defence by ignoring the evidence, and it still boils down to "I believe God did it". Despite their intelligence their motives are the same as the less educated advocates of creationism. For example, check out Michael Behe's performance in the Dover School board trials, I think this typifies the type of person you are talking about, and the disingenuous nature of their argument. There's a little bit about it here (and I can recommend the full lecture if you have time on your hands, Ken Miller is a very good speaker, and provides a very interesting account of both the trial, and the evidence on display):
I think it is telling that in three years of going to palaeobiology/palaeontology conferences I have never met one professional researcher who has anything but antipathy towards creationist ideas. Most (rightly) view creationism as antithetical to both the scientific method and stifling inquisitive nature of science. And this is why it is so important that school children aren't taught such ideas in their science class. If they are taught "here is some scientific evidence against evolution" (of which there is none
in conflict with evolution, but students can be given examples of genuine gaps in our knowledge as ‘proof’ against evolution) then the idea and clear implication is that God then wins by default. That is not how science works, and it will also make those children think "well, God did it, there's no point in trying to work out another reason" instead of "hey, I wonder why that is, maybe I should become a scientist to answer questions like that".
If you teach children this is acceptable science then you lose a generation of scientists. That’s a whole group of people who - if it wasn't for poor science education marred by religious dogma - could be the scientists working on cures for diseases, new technologies and a whole host of other innovations which we tend to take for granted. They won’t feel able to highlight areas which need more work, or gaps that need filling because creationists will jump on board and try and fill the gaps with God. They won’t want to try and find the answers to questions that puzzle them, because God did it so why bother doing any more work? Even then, if they want to answer those questions, they will have been taught the scientific method so badly that it hinder them massively at a university level, because kids listen to their teachers. If their teachers tell them something, they will most probably believe it.
Anyway, my point is that people should be free to learn whatever stupid things they prefer; reality usually deals pretty harshly with opinions and views that are nonsensical if you're a reflective person. And, if you happen to be a person who's not reflective and/or intelligent, you're not likely to have any impact on people whose views actually are - rather the opposite
Again, I agree they should feel free to go onto a creationist website and read all they like about creationism if they want to. They should not be taught it in science. Reality may then at some point “deal with them harshly” due to their beliefs, but by that point it is probably too late for them to make the most of any opportunities to study science or further their scientific education. I would also maintain that in huge areas this is will not be the case. In a recent gallup poll I believe around 70% or the American population does not believe in Darwinian evolution. These people are not dealt with harshly, and end up holding back science, and ultimately mankind’s development.