Over the top? Not really. Striated Caracaras are often described in similar terms in the Falklands. And the facts, presented by the article, support the eagles: namely that Great Cormorants weren't found breeding in Maine until the 1980s, whereas the eagle population in the continental U.S. has recovered only to 10,000 currently compared with 50,000 historically.
I did get a laugh out of "double-breasted cormorants" (i.e., Double-crested Cormorants). A single-breasted bird would be real news!
I just find it humorous these folks attributing human characteristics to wild animals. Just can't picture the Eagles wearing pants below their butts and engaging in racketeering activities.
They are primarily scavengers, and will steal food from other species or other eagles, which is why Benjamin Franklin considered them unsuitable as a national bird (maybe after the TARP he'd feel differently?). Also, I believe the article said many of the raiders are immatures, so that's another way the gang reference makes sense. Keep in mind that general-interest writers try to use fresh and interesting language to draw in readers; overall, as I said before, I thought the article was quite fair to the eagles.
This brings back to mind an old hunting mate who served as part of "Operation Overdue" when as part of a contingent of New Zealand Police he took part in the recovery of the bodies of the Air New Zealand DC10 crash into Mt. Erebus in 1979.
Ian never recovered from that ordeal, he retired from the NZ police came to live in Australia in 1983 bringing with him an obsesive hatred of all birds of prey the reason can be found in this link and I warn it is grim reading indeed.