Hello T-C: First of all, as anyone working on a computer should know, 10 + 10 = 100, or did your home schooling not include binary arithmetic?
If not, you should check to see how successful you are in trying to get a job in the computer industry. Imagine if all American kids were denied an education in the disciplines germane to advanced technology. Then where would your country be with respect to its ability to compete in this modern world and defend itself and its ideals?
But far more important, did your home schooling cover the history of the age of exploration? This was the late 16th to mid 18th centuries when all the great European nations set out to explore and exploit the rest of the world. You would have learned of the great explorations of Spain in South and Central America, of Portugal in Eastern South America, of England and France in North America, of the Dutch in the East Indies. One country, and one of the richest and most powerful at the time, is strangely missing from this roster: Italy. Or as it was known at the time, the Papal states.
Why was Italy alone left out of this booty that so enriched its neighbors and rivals that they quickly surpassed Italy in power and influence? A major contributing factor was that when Galileo was invited by his friend and admirer, Maffeo Barberini, who was to become Pope Urban VIII, to defend his beliefs in a sun centered celestial model, Galileo told Barberini that he only had to look through the telescope that he had made and see moons orbiting around Jupiter to realize the the Earth was not the center of all celestial motions. Barberini'a response was that if this was what the telescope showed and in doing so it contradicted scriptures, the the telescope must be the devil's instrument and he refused to look through it!
As a consequence, while telescopes and other optical instruments were not outright outlawed by the Council of the Inquisition, the making and using of such instruments was strongly discouraged and could lead to serious social and business problems. So What? As you put it, what difference would it make if no one learned about optics and optical instrument making? The difference is that without these instruments you cannot sail across an ocean. The profound importance of having the latest navigation technology will be evident to you if you have a GPS receiver and are aware of the military history of the GPs program.
While one may argue whether the entry of Europeans into the Americas, with its decimation of the native population and their culture, was a good thing, one cannot argue against the obvious beneficial impact it had on those nations the pursued the science and technology to gain their new discoveries.
A more recent and poignant example of the cost of sacrificing scientific truth to doctrinaire ignorance is the Lysenko affair in the USSR. Trofim Lysenko was a politically adroit but scientifically half baked biologist who became a close comrade of Joseph Stalin and from his position of political power was able to impose on all Russian biology a non-Darwinian and just plane wrong theory of evolution (it was closer to a Lamarkian evolutionary model that was construed to reflect the dialectic philosophy at the basis of communism). This theory was used to guide the development of agricultural to meet the increased demands of Russia's growing population and variable weather. The results were disastrous, and several years of major crops failed, not unlike what is now happening in North Korea. Russia had been the worlds largest producer and holder of gold, but all of their gold reserves and production went into buying agricultural imports from the west. So a nation that was trying to promote itself as a superpower and the one with the 'right' economic system was not able to feed and clothe its own people, but had to supplement its meager production with imports from its worst enemies. (Whoops! Spell checker almost changed that to 'worst enemas'.)
So when you ask why scientists are so ardent in defending evolution, a major part of the answer is that they love their country and the values it stands for and don't want to see it slide into technological impotency due to doctrinaire ignorance.