I don't think it is fundamentally the same question. If someone was about to throw a brick through a window I would say "Hey! Don't do that". But I wouldn't wal

I don't think it is fundamentally the same question. If someone was about to throw a brick through a window I would say "Hey! Don't do that". But I wouldn't walk past a smashed window and think to myself "Better go fix that window". Separate to that I also think that the question of bringing back a species like the Quagga is very different to bringing back the Mammoths. The Quagga went extinct recently and directly because of our hunting them. If we breed new ones, they'll likely fit into the ecosystem as it is today and may even thrive. Mammoths went extinct an extremely long time ago, the environment is totally different to when they were alive, we have no idea how they would impact the ecosystem today. Maybe they'd be totally unfit and would only exist as pets, or maybe they'd fit in great and drive some other animal or plant to extinction as their population explodes as an invasive species. The question of "Why bring back extinct species" is the same as "Why not bring some new different species into Australia"