I see his reasoning and, in the case of badgers, I fear he's right, but it has to be very, very carefully thought out. Too often new species have been introduced with insufficient forethought and culling has gone ahead with gusto to extremes. Not all badgers need to be culled. There are setts in the east of England, where the population is much more sparse which are TB free (so I've read).
And how does his theory fit with the rise in hawk numbers? More marsh harriers has resulted in plummeting avocet numbers. But the marsh harrier, a native bird, is at the top of it's food chain.
Wicked Little Letters? (funny film of a long-forgotten case)