Portland is probably the best biking city. It’s not perfect but in many neighborhoods it’s very cumbersome to drive and easy to bike. Drivers are also much less hostile in general.
Of the Tier 2 American cities, I think Minneapolis is the best at accommodating bikers, winter climate excepted.
The big difference: outside of urban centers Europe has a lot of paved paths between towns, that's something that spotty in even bike-friendly Oregon.