I haven't read Red Mars but these are both very different from an abiotic landscape. You can easily go back to an abiotic landscape on Mars because that's the default. It doesn't take delicacy. And, an abiotic landscape is extremely simple compared to an ecosystem. We can easily predict what will happen if we go back to one.
The 'we' here is the issue. Who is we? The human race do not share complex holistic goals, organisational frameworks, or even aesthetic preferences. It's a miracle cooperation exists at all at transnational scale. The hope that it could serve functional purposes - rather than alternately facilitating the enrichment of the very few, and constraining the worst excesses of that wealth transfer - seems to beg the question, how?
'We' don't truly care about anything, there is no we once the net gets that wide. Don't get me started on 'should', a word that shakes its head in impotence.
1. refuse to engage in biome modification to save soon-to-be-homeless species like the Axolotl,
2. are willing to go to great lengths to preserve existing biomes exactly as they are, such as opening up owl hunting permits to protect the western US's shittier owls from encroachment by the dominant eastern species, and
3. are trying to revive mammoths and dire wolves to increase biodiversity.
If we truly care about biodiversity, we should probably decide upfront why we aren't protecting some of the 400K species of beetles or 150K species of flies (together making up ~1/3rd of all animal species) instead.
Personally, my preferred answer is simpler: embrace human aesthetic preferences, rather than pretend we're doing all this for some altruistic, scientifically-supported cause. Not only should we respect nature, we should respect its inherent capacity for change and disregard for human morality. Nature is ambivalent towards mass extinctions, much less specific ones!
TBH, the Red Mars books' discussion around when and why to preserve abiotic martian landscapes may have radicalized me on this issue...