Poor (cheap) practices earlier in the process (aka life of the chicken) could cause lower quality meat, fewer nutrients, more likelihood for nasty stuff. Washing the germs away doesn't necessarily wash away the effect of that.
I think they'd argue "cleanliness" is not the only aspect of what "good" is. The chickens' diets and living conditions affect the quality of the chicken. To say nothing of the animal cruelty angle...
"The end doesn't always justify the means" the saying goes, therefore for the end to be "unequivocally good", the means has to be taken into consideration. This so called "eww" factor I think is a gross understatement of animal cruelty, other injustices and poor practices
Because the purpose of the steps is to hide faults and failures in the process leading up to the final product, and this means that any failure in this process is _likely_ to lead to a bad/unsafe/unhealthy product.