Depends, Stefan. In some of the cases described, what is taking place is loss of habitat, in which case the collected specimens might be doomed anyway. For example, collecting snakes from a construction site. Once the building goes up, the snakes have already lost their habitat, and apart from finding a new one quick (where they would still be subject to predation and competition with other predators in that area), they will die anyway. At least catching them would prevent their immediate demise, even if the end result for the immediate environ is the same.

I look at it the same way I looked at my own attempts to rescue snakes: in my neighborhood, the snakes have already lost much of their habitat to humans, and the more they encounter humans, the more likely they will die. But at least by catching them and moving them, I hope I'm giving the individual specimens a chance at survival. Granted, I don't know how much of one (they still have to compete with other species), and the problem with loss of habitat is still an issue, but it's better than seeing their headless corpses lined up along the street for the garbage collectors, IMHO.

Bottom line: if they are already losing their habitat, and relocation cannot guarantee their survival, then collecting the animals that are going to be killed anyway isn't going to have the same impact as collecting wild specimens haphazardly with no regard for the local population.