Ah ok. So you just think it's "gods plan". Meaning you don't have any idea why you think the way you do other than "god decides" Gotcha.
ok rather than god's plan how about this, the bringing back of a mammoth, a massive beast that towers over our largest land mammals can have catastrophic effects on the environment, mammoths are big creatures, no doubt about that, that in mind they eat a lot of food in order to sustain themselves. When we bring one back we risk disturbing the balance of nature, not any of that spiritual stuff, but simply the fact that if we bring a mammoth back the following can very likely happen
1) bring back mammoths and release them into the wild, everyday it eats a ton of food to sustain itself
2) other animals in the area starve because the food that they were supposed to be eating was taken by the mammoth, herbivores die, carnivores then die because of the lack of prey,
3) a large number of animals in that area goes extinct because of lack of food causing them to die out.
I don't think it's really worth for dozens, or possibly even hundreds, of animals to go extinct in exchange for bringing back one animal that went extinct thousands of years ago.
Then there's also the fact that it's cloning we're talking about. I'm all "science yay!" for the most part, but I am strongly against cloning. While it is true that it hasn't gotten to the point where we are cloning people (and quite honestly I hope it doesn't) but cloning is without a doubt an abomination against nature, the dead should stay dead, and the living should live until they die.