... and you totally ignored NEC 110.3(1) (8): "Other factors that contribute tothe practical safeguarding of persons using or likely to come in contact with the equipment".
The issue if not about the ampacity of power cords, wall receptacles, etc.. The issue is a "Listed" appliance can and is being interfaced with a branch circuit that is beyond the Listing and/or labeling requirements of the "Listed" appliance. It not "all bets are off" at the consumer level. Such thinking totally ignores the "Testing for Public Safety" of the Listing effort. The Engineers and Architect's of Record and well as the local regulatory inspection agencies are NOT doing their job. The installations cannot be NEC compliant because latent fire and shock hazards do exists ... and the consumer doesn't even get a vote!
The smallest standard size circuit breaker is 15-amperes. Do you really think a "Listing" agency, such as U.L., AGA, CSA, ETL, etc. would put their listing mark on a product that couldn't operate safely from a 15-ampere circuit?
Does it make any sense to protect a fractional horsepower bathroom exhaust fan with a 20-ampere circuit breaker? A 15-ampere circuit breaker would provide more protected ... and is most likely what the "Listed" equipment is rated for anyhow ... because of it's fractional horsepower load.
Horsepower available from a 20-ampere receptacle: 746 watts per horsepower/hr. However, a motor is not a purely resisttive device. It has inductive and capacitive characteristics. Subsequently to answer your question, I'll need to know how many vars (a measure of imaginary power) or volt-amperes (a measure of total power), or the power factor of the motor to answer your question. In addition, is the line to line voltage 120, 240, etc? Makes a difference ... but obviously you already know that!