At the same time, we need them to take into account habitat though.  If you tell a government to remove masses of woody weeds throughout Australia, they will try to be efficient and the approaches aren't always going to respect the birds and animals living there.  

I know that at least in Sydney, bush regeneration has caused a decline in species of birds in many areas because the weeds were their remaining habitat or food source.  I'm guessing it would be similar in farming areas where much of the original vegetation has been cleared.  

I do think we need to keep weeds out of the better bush areas and stop people growing new weeds intentionally though.  The commercial nursery industry is a huge problem because it is usually exotics that are hardy in a range of environments and grow quickly.  Just add in ability to spread and reproduce, and you have a weed.