I don't see resurrecting extinct species as unethical per se. It's a question of doing it responsibly. For example, creating a large numbers of an extinct species and releasing it into the wild would've likely have an unforeseen and disruptive effect on the environment. But under controlled and limited conditions it's fine, and if anything it could provide may invaluable opportunities to science.
This, i'm also in favour for it, for research proposes. There is also a little Siberian island in Russia where they can thrive, i don't know how it's called (but it's nicknamed mammoth island). Others can be in the zoo and others can be used for research proposes as long as the techniques being used are ethical.
