I wouldn't say it's ASB, especially considering the divergences and subsequent butterflies that have already occurred in the timeline. It would be very easy for America to experience a "red scare," especially after a successful communist revolution in Germany. If Red Germany or the USSR were to try to, say, incite a communist revolution in America that would most certainly turn America against them. And I wouldn't put it past the Comintern to try that.Yeah, US entering on the side of the capitalist powers is ASB. Roosevelt admired Stalin (even before WWII) and is far more focused on the Japanese "rising sun" than the comintern in all likely hood. The comintern won't care about Japan and will likely be more than happy to accommodate a destruction of a threat in the East.
Potentially actually this may lead America to become a breif co belligerent against the Comiterm, as the Soviets may take the chance to seize Manchuria and then perhaps do a joint Invasion of the Islands with the US.
There's also Mexico. Perhaps there will be a Comintern version of the Zimmerman Telegram? I believe its too late for any interference in the Mexican Revolution - but a more socialist/leftist Mexico after the revolution could easily make Americans fear communism as well.