Another is that you don't paint yourself in a fool's corner by getting your facts wrong and misinterpreting what actually happened.
But also, importantly, and one of my favorite reasons is that when you bother to read history and understand what happened earlier, you're simply able to see reality in its fullness and therefore put the present day in a wider, richer perspective. That's something I find interesting at any time, but which I always find most-especially valuable when a controversial issue in the present day had a counter-part in the past, but from a completely different perspective than is ever suspected.
I am currently (still...hey, it's 855 pages) reading What Hath God Wrought, the Pulitzer Prize-winning book by Daniel Walker Howe, about the communication and transportation revolution that helped transform America between the War of 1812 and the U.S.-Mexican War. And yesterday, I came across a remarkable passage.
It concerns the issues that lead up to Texas independence, beginning with when the territory was still a part of Mexico. The Mexican government had given American Stephen Austin the right to colonize the sparsely populated province, in hopes of attracting settlers. What Howe writes is --
"After the Mier y Teran fact-finding commission confirmed fears about U.S. intentions toward Texas in its report of 1829, the Mexican Congress passed a law suspending immigration from the United States in April, 1830. Austin got an exemption from it for his own recruits, and others found it easy to to slip through the border. Mexico suffered the problem of illegal immigration from the United States..."
Some things need no comment.
But sometimes the fingers must type or burst. All I could think after reading that was, gee, just think if far-right Mexicans had risen in outrage and demanded more security at the border, insisting that a wall be built to keep all the illegals out. If they had, then the outpouring of illegal Americans over the border would have stopped, there would never ultimately have been enough independent-minded outlawed insurrectionists calling for secession and starting a rebellion -- and all those Texans who today keep crying they want to to leave the United States...would have gotten their wish. Because they'd be Mexicans.
No wonder Texas officials love to require history books be rewritten for schoolchildren.