One has human moral responsibility, the other doesn't.

I actually do think, if we solved all the other problems in the world and had time left over, it would be right to intervene in nature to stop the harms you described too, and that conversation is a pandora's box of its own. But I don't think the upshot of these harms in nature is that we're also allowed to engage in similar harms at any scale we choose, as long as the badness isn't as bad as what happens in nature. Mainly because that comparison sidesteps the role of unique human moral responsibility and implies an unmade argument that analogies to nature can serve the function of authorizing human-initiated moral harms.