Why do americans believe they were the ones who liberated europe?

when they came marching the war was almost over. the russians lost about 30 million soldiers and civilians fighting the nazi's. Hitler was concentrated on russia which he feared most, not on the US, and his army was bogged down and decimated in stalingrad. The US deliberately waited on the sidelines and watched over 60 million europeans lose their lives and then came claiming victory. It's still an accomplishment to lose 50.000 soldiers to an already dead enemy. America stole european technology to build its own industrial complex like the space program and all the computer industry.