Why would anyone be opposed to de-extinction?

[muriel_volestrangler]

107. "as we colonize other planets" is hundreds of years in the future, at best

The questions of how many sources for clones would be needed to produce a viable gene pool, what subtle damage to DNA will have happened (older living parents have more likelihood of producing offspring with genetic diseases; what happens to DNA that was in a body that died would need to be known before any serious attempt at resurrecting a species is attempted), how any learned behaviour is taught to them, when there's no examples in the wild for us to observe and imitate, are all significant ones, that need a lot of research.

In the mean time, there are many species that we can stop from going extinct with far less effort - all the environmental work needed for them would be needed for a resurrected species too. Plus the tiny matter of climate change. We are neither at the point where we can try it with any real idea how it will turn out (which means you're doing animal experimentation), nor devote resources to it that couldn't be more productively used with living species.