Maybe it's the "Don't cry wolf" theory. If politicians start using gas chamber analogies all the time, it could lessen the impact. If it becomes acceptable, politicians will be using such references all the time.
Like you can't use the N-word in a sentence even when it's in support of the black community. It's too toxic.
Realistically, how is that supposed to work? It might provide a funny sketch for Key and Peele, but come on ...