I love science and have no issue with evolution and agree completely with the idea of a science camp that would enable the children to do what you advocate in your post, and ask lots of questions about the process to boot. I just think the average child would get very bored watching it all in action on a farm.
I also think the average child who goes to a religious run school or belongs to a family that believes in God would find him or herself quite conflicted by Camp Quest. I get the strong impression that science/evolution per se is not what Camp Quest is all about. A child would be left in a position of having to choose between the false antithesis of 'Religion' in the form of invisible unicorns on the one hand and 'Science' on the other. As has been mentioned upthread, there is not necessarily a contradiction inherent in belief in God and acceptance of scientific truths.
I wonder as a Catholic, why the smug invisible unicorn challenge is included in the camps. Science is for all, not just for atheists or secularists. Some of the other items on the prospective, including 'pseudoscience, astronomy, logical fallacies and much more!' make me wonder about the intellectual freedom of such a camp.
My DCs have enjoyed and benefited greatly from camps they attended in the US for G & T students that were truly secular (in the American sense of being non-denominational, which I consider a good working definition of the term) without the element of sneering, or imposition of a particular philosophy that seems to go along with this particular one. FWIW, the US site of Camp Quest is far more 'in your face' about promoting atheism than the UK page seems to be. Much more of a soft focus for the UK, whereas the US is unapologetically hard-edged. I would not send my own DCs either to the US or to the UK camps. It wouldn't be fair to them to place them in a position where they would feel uncomfortable. Sad to see the world of science co-opted in the service of 'the assertion of a universal negative' (Chesterton's phrase)
DD1 did Chess one year and Biology the next. DD2 did a Harry Potter-based creative writing and drama camp for her first year and The Oregon Trail the next. She wanted to do Robotics but that one filled up within minutes of registration opening.