The US was more than hostile, we had soliders on the ground in Murmansk and Vladivostok. Russia for a few years was in a China like scenario with outside powers.
US sent soldiers to secure shipments sent to Tsarist Russia. And surprisingly bolsheviks declared themselves "free" of any Tsarist Russia financial burden(s), so allying with Whites was logical.
So it wasn't hostile at that time.