In a broad sense I agree - science is not just a fact based subject. Experiments are the foundation of deciding what theories are correct and which are not - but practical work is not really the biggest part of science.
To quote Isaac Newton "If I have seen further it is by standing on the shoulders of Giants". The foundation of science is reading the work of other scientists so you do not duplicate it, and writing up your own results for other scientists to view. This requires a number of skills, namely
- Interprtting written facts
- Finding flaws in the process used to arrive with these facts
- Interpreting the results from your own experiments
- Forming theories based on these results and testing them
All of these can be perfectly well assessed through tests. Admittedly they are not as fun, but they are probably a more important part of science. Einstein didn't arrive at his theories just by shining bits of light on things, and Newton had to do much more than just let an apple fall on his head.
I admittedly am not American, but the science course I am taking does involve a fairly large part practical work (20%). IMHO this is a fair representation of how important practical work is.