Everything was "invasive" at one point or another.  Archaeologists are trying to determine when the squirrels arrived on Chirikof Island.  They were there 2,000 years ago.  Were they "invasive" then?  Did they drive out older species?  The first humans to arrive in Alaska were probably "invasive" from the point of view of the animals who lived there at the time.  Things change.  Get over it.  
Interesting point from the FWS FAQ document I found, though.  They don't know whether they'd harvest the meat from the cattle they'd kill or not.  Seriously?

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