Where is the contradiction?
Commander, it's painfully obvious that we need to shoot these things down whenever and wherever we see them. We have to stop that from happening at all costs.
It's pedantic I know, but the use of "that" is ambiguous - it can easily be read as him saying that we need to stop them from being shot down !
The simplest fix would be to simply swap the two sentences around so that it reads:
The Corrupter presents a major ground threat due to its large crew complement. More than any other craft we've encountered, the Corrupter is purpose-built to deliver large alien forces to the surface. We have to stop that from happening at all costs.
Commander, it's painfully obvious that we need to shoot these things down whenever and wherever we see them.