What these structures remind me most of is what you would find in a sour heavy crude oil. In fact, I can guarantee the person who named this website has never looked at high resolution mass spectroscopy analysis (like an FTICR-MS) of any type of petroleum, or they would have named it "this chemical is probably being pumped out of the ground right now".
Some of the most powerful explosives are made by attaching nitro groups to stressed ring or cage structures.
When the nitro group breaks apart, the nitrogen finds another nitrogen from another NO2 and forms N2 gas, which is highly stable due to its triple bond, so this part of the reaction releases a lot of energy and produces a lot of gas, and is very fast since it does not depend on any other sub-reactions. And stuffing lots of just nitrogen (without oxygen) into a molecule is in itself a way to make it very explosive - see azidotetrazolate salts.
In NO2 decomposition, the oxygen then goes on to find carbon to make CO2, and hydrogen to make H2O, releasing more energy and producing more gas. But this first requires breaking down the relatively stable bonds in the hydrocarbon, so it actually consumes energy from the NO2 decompostion, before it releases more energy than it consumed.
Then stoichiometrically you want to ensure that you have enough oxygen for all your carbon and (ideally) hydrogen, or you'll end up producing a lot of "unburnt" stuff which is inefficient. Notice that for each carbon in a linear hydrocarbon chain (-CH2-) you need 1.5 NO2 groups to get a complete reaction into CO2 and H2O. If you only have 1 NO2 group, CO2 will be formed and you will have excess H2 which is not combusted.
Now as you say there are some stressed rings or cages that are hideously sensitive explosives, precisely because the hydrocarbon bonds have also had their stability reduced. But these typically are not practical explosives. For that you want the stuff to be a solid at a wide range of temperatures, you want it to be non-sensitive to friction and impact, and you want it to have a low vapor pressure. These are all details which depend strongly on the internal structure of the molecule.