Although the word explode does in fact derive from Exploud, it is not because of any ability they have to actually explode. If that were the term's etymology, we would call exploding electroding as in the old Kanto dialect, for those pokemon are most strongly associated with the technique, or any number of other terms for other pokemon capable of learning how to detonate themselves. Instead, we call it exploding, after a pokemon which may not blow itself up, but has the remarkable ability to trigger detonations in others.
Although these pokemon are deaf and have been since birth, this works to their advantage, for Exploud can focus on the vibrations which their sonic attacks create, undisturbed by their actual sound. Unlike their earlier forms who could rely only on speakers and their voice, these pokemon use their numerous pipes to alter the volume and frequency of their calls, and one of the first things they discover is which sounds cause land mines, sticks of dynamite, bombs, or pokemon to explode at their command.
Ever since Exploud were first domesticated, explosives have been a rare weapon in Hoenn, used only for surprise, for they can be disarmed or turned against the user by an enemy pokemon's call. Yet what a surprise it is! A minefield in Hoenn is not an invisible wall, but a trap; soldiers charge across the field without a care in the world, and seconds before reaching the enemy the ground detonates beneath their feet and the whole army is lost! Although Electrode often form the mines in this sort of surprise attack, the pokemon bombs are outshined by bright light and debris and the loud call of "Exploud!" is the last thing any survivors hear before the blast.
This is why it is called exploding.
