Did the timing of Communist inspired wars especially after 1921 influence the American response?
The period between 1921 and 1941, the only Soviet involvement in wars were its "invasion" of Eastern Poland ( as agreed by Stalin & Hitler ), Stalins defensive and offensive struggle against Germany, and Stalin's brief war with Finland. America was unhappy with the Nazi-Communist invasion of Poland and the Soviet war with Finland but had no real response.
Later of course the Soviets and the US, Great Britain and French freedom fighters had to fight with Stalin against Germany.
The next "communist war" was a communist revolution in China in 1949-1950. This disturbed US policymakers and the US public greatly. The US response was one of containment and support of the "other China" on Formosa, now Taiwan.
The war sparked by North Korea against South Korea was met by UN forces against the communist attempt to take over South Korea. The US bore the brunt of lost troops as China unofficially aided communist North Korea. A truce reset the old boundary there, and America's policy of containment continued right into the battle with communist North Vietnam. There containment failed. However, from that point on "communist" inspired wars, with the exception of the communist led Cuban revolution, had little effect in terms of troop movements. To clarify Cuba's revolution, Castro did not declare himself a communist until his revolution was complete.
In summary, the US response to communist led "wars" was to fight in Vietnam and Korea, and become extremely alert about Cuba. The policy of containment basically ended when the USSR collapsed and China made no real efforts to expand.