Marketing BS.

People will flock to the bigger number without understanding anything about it.

Same as vacuum cleaners today that market the wattage as a feature, as if using more power makes it a better vac.

"Oooh, this one says 2000, it must be better than this one, it's only 1400."

There's a lot going on here, most of it boils down to marketing.  The maker of that washer is trying to impress potential buyers by giving the impression that their motor is more powerful than the usual motors for competing washers. They are hoping that this will make potential buyers assume the washer is in some ways "better" than the competition.

In all reality, appliance "horsepower" ratings are very often not factual. It can be as far-fetched and dishonest as the overstated shop air compressor or shop vacuum HP numbers involved in lawsuits; to the intentionally understated horsepower of the 30's and 40's fridge compressors. The shop air compressor makers were lying in an attempt to make their generic product stand out from the competition as more powerful and therefore more useful in a workshop. The fridge makers were talking up low energy consumption when electricity costs were extremely high. It all was a marketing thing.

The agitation speed of a washer is chosen to provide the best cleaning and least wear on the clothes; and it seemed that a 1/2 to 1/3 HP motor was usually adequate to power this.  The larger motor might allow for more overloading of the washer before the motor was stalled, but likely the transmission or belt would slip before the motor was a factor. 

As for trying to determine actual AC motor HP delivered to a load; based on current, that is a more complex task and not one which can be done by multiplying volts and amps.  

In addition to what Chetlaham said above, I want to add more details to back it up.

Horsepower and watts are both measures of "power" and can be mathematically converted from one to the other.  You can make calculations, based on actual measured values taken with the correct instruments, while the motor is running and determine how much power is being delivered to the motor. This is a snapshot in time of how much load the motor is seeing, and how much mechanical power is being sent to the load attached to the motor shaft. It doesn't represent the motor's rated horsepower; unless the load is known to be exactly 100% of the motor's rated horsepower.

This calculation is not complex; however you need to know the power factor (Cos θ) as one of the factors in the calculation. This value changes greatly as load is applied and removed from the motor's shaft.  The only way to measure power factor is with meter designed for this purpose.  The meter must measure BOTH voltage AND current at the same time, and compare the waveforms. The amount of offset between the peaks of the sine waves of voltage and current is used to determine power factor. It is done on a waveform level, and not possible to measure with two separate meters for both voltage and current.

The amplitude of the voltage waveform, the amplitude of the current waveform, and the offset of the peaks of the two waveforms (in realtime) are necessary to calculate motor watts and therefore estimate horsepower delivered to the load. It is easy to use a meter such as a Kill-A-Watt plug in meter, to measure these values.  Static values printed on a nameplate for a motor are used mainly to know if the motor is operating outside its design limits, and to select the proper protective devices.  

This washer has an induction motor. The motor has an inductive, lagging power factor. Even with no load, the motor will draw a significant percentage of its rated amps.  As load is applied to the motor's shaft, the power factor changes dramatically, making up a significant part of the difference in the no-load power demand versus full-load power demand. Because power factor is always changing (based on load) with an induction motor, and has to be measured dynamically, it is not ever possible to measure watts, and thereby estimate HP based on separate current and voltage measurements. 

Why does it matter to the electric utility?  Think of an engine turning a generator, cables from a generator to a motor, and a motor turning a load.  If the motor is running freely without a load on the shaft, the engine powering the generator will also see very little resistance turning the generator input shaft. This is because the motor is using little power (watts), because it is putting out very little power (HP.)  The generator also is not seeing a high wattage demand from the motor.  It passes that light load of power back to the prime mover powering the generator. The engine will see little resistance to keep turning the generator shaft. It will therefore not use very much fuel. Prime mover load,  fuel use, and fuel cost of the power plant is heavily dependent upon real power (watts) taken from the power plant, more so than current. 

So to summarize:
The load placed on the motor shaft takes power (in the form of horsepower) from the motor.
The motor takes power (in the form of watts) from the electrical utility's generator.
The generator takes power (in the form of horsepower) from the prime mover (engine.)
The engine takes "power" from its fuel source in the form of fuel flow.
Fuel costs money to replenish. Therefore the amount of watts drawn from the utility directly impact fuel cost.
This is how home users of power are billed in many areas. They are billed by wattshours because that represents their share of the fuel used by the utility. 

There are many good online resources if you want to study this more deeply. It is a concept I deal with often when working with generators, switchgear, and electrical protection equipment. It can be an abstract concept and there are people who never grasp it and constantly struggle, even in the industry, with this. Anyone who blatantly states this doesn't matter is really ignorant has no business commenting on such matters. They should, in fact, probably hire and pay for an electrician to change the next light bulb for them. 

Sincerely,
David