This form of argument does not seem to apply to every parallel drawn between any two things. It seems to apply specifically to comparisons that are very close fits with dominant cultural trends.
In 1800s Britain, it could be applied to reject claims such as "cholera is caused by the jews", but it could not be applied to claims such as "cholera is caused by contaminated water pumps".
Similarly, the claim "prostitution was made illegal because the Plumbers and Deliverypeople Union wanted exclusive nibs on spontaneous sexual encounters" would be impervious to this 'sword', because blaming plumbers for the problems of society is not a current trope of our culture.
Disregarding the merits of this particular instance, that seems like a reasonable general heuristic: after all, if some conclusion is socially desirable, then people may reach it even when it's not supported by the preponderance of evidence.