The article is accurate, but sloppily composed. It does not clearly distinguish between Circumvesuviana line train stations and Trenitalia (long-distance national rail) stations. It also does not make sufficiently clear that "Pompeii" can mean both Pompeii Scavi (the ancient city, excavated and with three turnstile paid entrances) and a modern city that may well (I haven't stayed there) be an attractive place to stay.
I have often noted that Sorrento is a bit of a purpose-built resort town, but it has a spectacular location on a cliff (if only one beach, but that's one more beach than Pompeii has.) I doubt that modern Pompeii has very much charm, either. But Sorrento is better located for the vast number of people who want to make a Daytrip to the Amalfi Coast. And it's really close to places like Sant' Agata sui Dui Golfi, which are trivial daytrips. (I mention Sant' Agata because it has a wonderful downhill walk back to Sorrento, for those with good knees and legs.)
The article is written (my opinion) from the viewpoint of a backpacker who has to save every penny possible. But there are vast numbers of penny-pinching sun-seeking Brits who stay in group-tour hotels just outside Sorrento, with a shuttle bus (not for me!) into town. The real issue with Sorrento is not the price, it's that it books up six to nine months in advance. So those who can't plan well in advance find it (although it's not actually so ... ) an expensive town. They have to take the places that still have rooms when they finally get around to booking.
Note that the ferry marina is a long walk and a 2 Euro elevator, or a substantial (if cheap) bus ride from the Circumvesuviana station in Sorrento.
OP Vijay, download a Circumvesuviana schedule. It does NOT run late at night. If you care about Sorrento and Capri, you should NOT stay in Pompeii.