So presumably unrivalled compared with other charging systems that aren't open to the public. It's not really a charging "network" either, so I agree the title is clickbait-y. Article is decently informative though!
However, a little paragraph puts that number in perspective by stating; "However, they do not include the many charge points installed at home or at workplace locations, which are estimated to be more than 700,000"
That's a lot of chargers. The number of petrol stations in the UK is below 9K and slowly shrinking as people transition to driving electric.
The UK is probably a little bit ahead on the US with it's charging network and itself a little bit behind on other countries in the EU. But 17k level 2 chargers isn't that impressive.
Amazon is probably doing a numbers game here and is prioritizing electrifying their fleet in places where fuel is expensive and the cost savings are higher.