As for us being a plague, we can be described as such in the borader meaning of the word, similar to plague of frogs or the like, mut not quite fitting the tighter definition of plague as in an actual disease. One species rising to dominance over all others is a natural phase of the evolutionary cycle, and has happened multiple times in the past.
Likewise, said species becoming too dominant and ultimately extincting itself and a large portion of other species by being too dominant is nothing out of the ordinary, either, starting from to ancient bacteria that chocked dead on their own feces; oxygen. The only "saving" humans can do is to save themselves from themselves. If they can't and exploit the world until they chocke themselves, boohoo. Business as usual, nothing out of the ordinary. Que next dominance cycle.