Not all speeding is created equal. I agree that 10 miles over a 30 mph zone is probably deadly, if it was properly zoned and not a money-grabbing move (it looks from the article that it was a correct limit, maybe even too high).
However, many speeding tickets (at least in my country and others) are due to low maximum speeds on roads intended as main thoroughfares.
I read here in HN that plenty of U.S. towns live off speeding tickets, see
http://www.foxbusiness.com/features/2011/10/19/town-that-liv...
http://www.9news.com/story/news/local/investigations/2015/05...
In my country they have some similar systems, and made even worse because they specifically target tourists and foreigners (especially Argentineans) for the ticketing revenue.
I work for an insurance company, and I've read some research that suggests that speed limits are improperly sent more often than not (a few times too high, but most often too low). Interestingly, accidents are going steadily down due to better cars. Other factors are much bigger influences than just speed (alcohol, stress, etc.), and insurance companies are introducing monitors for that. Hopefully self-driving cars will continue the downward trend :) .
IMO, dynamic speed limits, based on weather and road conditions and other stuff (lower on school days?), should be the default in the 21st century :) . Germany already does it.
Another problem was improperly planned roads, as in the article (another comment mentions that the road in question is a "feeder" road).