Yep, that's a good point! But these things are of course linked; we would not really have to worry too much about extinction if we didn't pollute and cut down the forest they live in.
Getting a species back from being critically endangered is possible, but extremely difficult. And getting them back from extinction is impossible. I know that some people (for some strange reason) believe that it's not that difficult to get them back as long as we have their DNA, but it is definitely a hundred times easier to protect them while they are still alive. Not to mention that no one has ever successfully brought an extinct species back for more than a few minutes at most.