When you look at a Soviet flag you see repented an ideology that caused the unnatural deaths of some 100 million people.
When you see an American flag, you see represented the First Nation in human history which enshrined in its foundation the concept of universal human rights, and which was instrumental is n defeating the Nazis, and which remains, in the main, dedicated to the final defeat of the Communists, although it is hard to know when or how that may happen. We beat the Soviets, but the Chinese remain committed to their ideology of tyranny, oligarchy, and the repudiation of the right to do anything but conform.
And of course our nation is suffused with Communists calling for a reversal of everything promised and protected by the Constitution. But the fact that they feel the need to insult and burn our flag indicates it still stands for human decency and a belief in the power of ordinary people to grow and prosper, when given the freedom to do so.