I think an underrated driver of this decision, debateably more so than cultural ties, would be financial ties. IOTL American finance skewed heavily towards the Entente and continued access to American lines of credit was one of the big reasons the British and French put so high a priority on maintaining cordial relationships with the US.
To be honest I'm not sure what kind of POD would cause US financial weight to be thrown behind Germany rather than Britain and France, but given that most of that came from Wall Street and not from the actual government one could argue that all it really takes is Germany doing better in the opening months of the war. That said, given the enthusiasm of JP Morgan jr. for the Entente cause (from
Wikipedia: "The firm's involvement with British and French interests fueled charges the bank was conspiring to maneuver the United States into supporting the Allies in order to rescue its loans") you'd probably have to have some pre-1900 POD to get anything other than a group of rabidly pro-British WASPs in charge of America's banking infrastructure.