Good point! I posed a similar question a couple of years back to the Noxious Weed Board (I believe it was in Bellingham, but don't remember for sure now. I seem to remember it was somehow tied to WSU.....so I don't know.) Anyway, the question concerned the lack of listing and lack of action to eradicate Himalayan Blackberry. Her answer was intuitive and I remember her words. She described them as a "love/hate relationship".
Probably as well-put as anything I'll hear concerning the assignment of the term "invasive".