yeah no matter which way the door swings. Whether your catching a garter(or whatever) and keeping it or clearing some forest destroying its home, that animal is displaced. Its not a bad thing, its just the selective process...
Giving a garter a chance at life by releasing it in another location free of human interaction just means that a toad/frog/worm may be in danger of becoming that snakes meal.
We fall short of thinking through things when we have the best intention of 1 animal in mind. You might be doing right by that garter, but screwing the toad in the mean time! The environment you realse the garter in is now either 1 up by way of predator in the food chain, or 1 down.
It is what it is. If no animal(including us) fell victim to premature death, then imagine how life would work.
If we take, and this might be a bad example and spark a crazy debate, war for example; people obviously die during war time. Whether it be just or not. Its just natural selection. Its sad, but again it is what it is! Got to look at it as a whole!