Have you ever heard the phrase:
"Those that don't remember the past, are doomed to repeat it!"
Understanding history allows us to better understand the bad unintended consequences that result from good intentions. Understanding past decisions and their consequences gives us the ability to make better decisions today.
Lets take "universal health care" for example. If we study the history of other countries that have this system of health care, we would understand that as soon as the government pays for everyone's doctor bills, EVERYONE will be at the doctor. Supply will be stagnant, but demand will skyrocket! Supply and demand tells us that this means prices will go up. But, because the gov't will have control over the prices (since they are the only ones actually paying now), our health care system will suffer from poor quality of care!
In Canada (where they have "universal health care"), the lines were so long that a new law was recently passed: No one can wait longer than 4 hours before being seen at the ER. Since the ER can't make that happen, they have been requiring the patients to wait outside in their ambulances for an hour since the clock doesn't start ticking until they enter the ER. So now they are short of ambulances to come save your grandma from a heart attack!
Now thats what I call unintended bad consequences resulting from good intentions! Knowing the history of this type of health care should influence your ability to make future decisions about it. Don't you agree?
Plus, people will try to "rewrite" history all the time in an effort to try to make some political point. By knowing the truth, you won't be suckered into their trap.