What they didn't say was that 4 Hiroshima bombs per second is diddly squat compared to the heat exchanged on the earth by natural processes. It's easy enough to rewrite the units so that the number becomes extremely small.
And people aren't stupid. The Hiroshima bomb statistic makes the believers salivate because they are entirely emotional. For scientists, it's obviously an empty emotional statistic of the type used by people who do not have logic on their side.
The general public doesn't care about the statistic because they know that global warming has been going on for decades which means it amounts gazillions of Hiroshima bombs. If anything, it makes them think "so why isn't it too hot to live already?" My guess is that their conclusion is that the climate scientists have made a mistake in calculating the heat and can be safely ignored in other things as well.
The statistic is a great example of the tin ear of the global warming enthusiasts. They simply do not understand how their views are seen by the general public and they do not at all understand the arguments of the other side.
The reason the Nazis made such great propaganda is that they understood what they were doing and they did it based on science instead of emotion. They saw propaganda as an art and science. The greenies are purely emotional and cannot deeply understand any theory, global warming or propaganda. The greenies publish anything that makes them feel good. The Nazis only published stuff that was capable of convincing people to their side. (Along this line, the ISIS have the worst propaganda I've ever seen. I don't expect them to last very long.)
By the way, the Nazis were big on environmentalism. They were going to use part of east Poland as a game reserve: