Certainly each side - the 'absolutists' and the 'constructivists' or 'humanists', as I've labelled them - accuses the other of hubris, and lays claim to humility. I see hubris on both sides: a pretence that we could ascend to an objective account of the world, on the one hand, and a pretence that we have the resources to live and act without a sense of there being something to which we answerable, on the other. So both sides are 'villains'.
I'm very sceptical about the prospects for 'big' environmental causes - 'saving the planet', halving the world's population, ending the exploitation of animals, and so on - but a person can ask him- or herself how he or she personally may exercise compassion or humility towards animals, vegetal life and so on.
Gardening is an excellent example of a practice to which, as Alasdair MacIntyre puts it, certain virtues are 'internal'. Good gardening requires a certain goodness on the part of the gardener: care, humility, patience, and respect, for example.