They don't. Science simply demands the same thing from IDers that it demands from evolutionary theory - if you want your theory taught in schools, you need to do research, submit papers for peer review, subsequently allow those papers to undergo scrutiny by the community at large, then have your major discovery published in one of the more major journals, at which point science textbook writers include your theory in college level textbooks, and eventually, if the theory is appropriate in comprehension level, it enters the secondary school teaching arena.
What IDers and creationists demand instead is special treatment, a.k.a. affirmative action for their theory, when its advocates aren't even really participating in the scientific method to start with.
Sort of like football fans complaining that the referee won't count imaginary touchdowns for one side just because their opponents have stronger players.
It did prevail, by about 1870 or so.
Also, we have come to expect dishonest debate from the anti scientists. Soundbutes, sophistry, equivocation, drug-induced perjury, ...
Thanks for your reply...well said.
However, evolution is NOT a fully proven theory...compelling yes, but not 100% established...Yet, the education establishment does not treat the subject as theory, but as fact, and they atack ANY descent...even from evolution scientist....
Please see my reply to CarolinaGuitarman.