The word "holiday" comes from "holy day." America's "holy days" include Memorial Day, Flag Day, "Independence" Day (although the USA didn't even win independence on that day), Veterans Day, and President's Day. And I'm probably forgetting a day or two.
President's Day itself isn't one to honor all the Presidents, only Washington and Lincoln, who were noted for building the nation through war. Indeed, war is the reason for the other holidays as well. War is the tie that binds the Union together. It was created through war, expanded through war, was "preserved" through war, and became a global empire through military force. Our country's obsession with the "sanctity" of the national flag stems from it being flown in battle. Honoring the flag is one way to honor veterans and those who died in war.
There is nothing wrong with showing respect for the sacrifices made for the country, but our militarism is over the top. The Founders of the Republic were themselves quite suspicious of maintaining a permanent army during peacetime, believing it to be an enemy of freedom. They were right: the rise of the "military-industrial complex" correlates the with erosion of personal freedom in the United States, so that today the President believes he can do anything he wants to anyone and justify it on national security grounds. But the United States never faced a genuine national security threat - a threat to its mainland - since the War of 1812. All other "threats," from nuclear war to terrorism, were provoked by our own foreign policy.
And really, America's war record is quite overrated. While General Washington deserves credit for keeping the army intact during the Revolutionary War, that was part of a wider conflict between France and England, and England lost mainly because it ran out of money. The War of 1812 did establish the country as one not to be messed with, but it failed in its invasion of Canada. The Mexican War was unnecessary, and the large territory we conquered heightened sectional tensions that led to the War Between the States. And that war, in which over 600,000 soldiers died, was both illegal and unnecessary; the Southern States did have a right to secede. The Spanish-American War was a cakewalk against the pitifully weak Spaniards, but we had no just cause to start it. Furthermore, we acquired a colonial empire from it, and then betrayed our own principles by putting down a rebellion in the Philippines, costing 200,000 Filipino lives.
World War I was a military "victory" for the Americans, who joined the fight after both sides were exhausted from three years of trench warfare. But our reason for entering it was nonsensical; German didn't respect "freedom of the seas" when "neutral" ships sent war materiel to Britain, but Britain didn't respect the freedom of the seas either. The post-war diplomatic catastrophe rightly convinced Americans to not get involved in other countries' wars.
American involvement in World War II wouldn't occurred as it did if it hadn't illegally annexed Hawaii and gained other Pacific possessions decades before. As it is, we joined the conflict just as Hitler turned his attention toward his east - which is where his ambitions were all along. While the USA whipped Japan and joined with Britain in liberating Southern and Western Europe, 80% of World War II was fought on the Russian Front. While this war lives on as the "good war," and is the basis for the militarism that persists today, the reality is that the communists, with our help, came away as the big victors of World War II.
Since then, the USA has often been at war, but they've been undeclared, which means they've been unconstitutional and illegal. And the military's record in this time is such that, if it was any other country's, Americans would make jokes about it. After initial success in defending South Korea, the USA wasted years and lives battling North Korea and China to a draw, and our military is still in Korea 55 years later. Despite killing a million Vietnamese against 50,000 American deaths, America lost in Vietnam. The USA expelled Iraq from Kuwait in 1991, but then embarked on a brutal and unnecessary regime of economic sanctions against Iraq, followed by a disastrous invasion. It "liberated" tiny Grenada, but was humiliated by Somalia - a starving country which didn't even have a government. It cowardly bombed Slobodan Milosevic's Yugoslavia for the crime of putting down a Moslem rebellion in its own country. We reacted to 9-11 by attacking not just Al Qaeda but also the Taliban in Afghanistan, and war is still raging there. Aside from Al Qaeda, none of these enemies had either the interest or capability of attacking the United States directly. Which should make us wonder, what was the point?
While many will spend Memorial Day in remembrance of the sacrifices of our brave men and women, I think the best way to honor them is to ask for what ends did they fight, and what the country really gained by resorting to war so often in its history. Can we really trust any President and/or Congress to decide when to use force - especially overseas against countries that pose no threat to us? Can we really trust our generals to know how to wage "asymmetrical" warfare against guerillas? To join the armed services in this day and age is the biggest leap of faith an individual can make, a leap I wouldn't take myself or suggest to any young person.