Lots of good points here. If history has taught us anything, it's that, if you appease an imperialistic dictator by giving him a swath of another country's sovereign territory, said dictator is completely satisfied and will never again evince aggressive or expansionist tendencies.
Examples range from Napoleon to Hitler, but there's another that hits closer to home. In 2014, an obscure former Soviet republic called Russia was led by a Vladimir Putin. In February, Putin annexed a portion of another former Soviet state called Ukraine and supported separatists who set up pro-Russian puppet states in two other areas. Despite fierce Ukrainian resistance and Western protests, Russia ended up keeping the land.
True to form, Putin never again disturbed the peace by invading Ukraine or any other country. Instead, he lived a quiet life as an equestrian and passed away surrounded by friends and family following a short battle with a fall from an eighth-story window.
Ah, yes, the lessons of history! Before you give yourself an "A", however, you should know what most serious sophomore students of history should have already learned: what history teaches us depends on the events chosen and the ideology that possesses you. (It also helps to know a little bit about the background of the events you choose to learn from.)
The event you invoke is the recent Russian invasion of Ukraine and argue - employing sarcasm - that based on the lessons of history one cannot cede territory to the aggressor because otherwise, presumably, his appetite will only be vetted and he will continue his aggression, and he will further encroach on your territory in the future.
(As an aside, the results of the Russia-Ukraine war are not yet knowable, and neither are its lessons.)
But in any event, let's take a look at a couple of other examples, and test your thesis.
How about the War of the Austrian Succession? It was started by Prussia, the aggressor, attacking and seizing Silesia, which was a part of the Austrian Empire. The war ended with Austria ceding Silesia to Prussia. Aggression rewarded? Right? A no-no under your argument because it will only whet the appetite of the Prussian aggressor to keep encroaching on Austria's territory. Actually, the next war, the Seven Years' War was initiated by Austria in an effort to recover Silesia. Austria failed. Nevertheless, within a few years Austria and Prussia, along with Russia, were partners in the partitions of Poland and after that, they were allies in the wars against Napoleon. Your lesson fails if we consider these events.
Let's consider the example of the Mexican-American War. The US aggressor ended up with huge chunks of Mexican territory, almost the size of the Louisiana Purchase. Under your thesis, one would think that the US has ever since been encroaching on and militarily seizing territory from Mexico. Hey, the southern border of the US must be south of Mexico City by now! Wrong. Once again your lesson does not work very well.
Under your lesson of history, one might conclude that if you do confront and stop an aggressor and deny him any territorial acquisitions, his taste for aggression will be blunted, and he will no longer threaten his neighbors. OK, let's have a look at World War I. In this conflict, the German aggressor was soundly defeated, its entire system of autocratic government overthrown, and replaced with a liberal democratic one. Germany was even stripped of considerable territories, its armed forces were practically eliminated, and the country had to agree to pay for the war. Well, I guess that solved the problem. Military aggression was confronted, defeated, and punished. No more danger of Germany attacking its neighbors. Right? Never mind World War II. Actually, your thesis leads to erroneous conclusions once again.
As I noted in the post to which you objected, Russia's aggressive designs toward the West have already been blunted by its inability to take Ukraine. It is time for peace. And part of the price for that peace will have to be that Russian majority territories, which were never traditionally a part of Ukraine anyway, will be ceded by Ukraine to Russia. You do believe in self-determination, don't you?