What’s the poet trying to tell us here? That the perfectly efficient Germans of his fantasies would not have tried this method because they would have realized, without even trying, that fires caused by incendiary bombs might have undesirable collateral effects offsetting their effectiveness as a body disposal method? Such reasoning fails to take into account the situation that led to this method being attempted. Tens of thousands of bodies lying in mass graves at Chelmno had to be removed, and burning them in huge fires seemed the best way to do that, so the question was how to make such huge fires, preferably with the least effort and at the lowest cost. Incendiary bombs were a simple and effective way to start large fires at high temperatures, which were just what was needed to burn all those bodies in a speedy and thorough manner. Incendiary bombs were something that could be handled by the small staff of SS-men assigned to the task (see above quote from Arad), whereas building fireplaces to cremate the corpses (the solution eventually adopted), and transferring the corpses from the graves onto these fireplaces, required time and a workforce of permanent camp inmates. And the SS-officer in charge of burning the bodies, Paul Blobel, was not at the same time a forest-keeper, and may only have started caring about environmental side effects of his work after he or his superiors were faced with complaints about forest fires caused by the body-burning. Such complaints from the local forest administration and/or other entities were probably what caused this method to be abandoned and a burning method perhaps less comfortable but more sparing on the environment to be adopted. What's the implausible part supposed to be?