It's written in the usual for sensationalist liberal style of the Guardian where he has chosen certain rare incidents and suggested that they are the norm. For example he suggests Di Canio's hand salute from 13 years ago is commonplace and recent.
The title suggests that a trend is growing but he is using past issues and seems to use Lazio Ultras as the common attitude of all fanbases.
It says racists incidents have risen in Italy and suggests it is due to growth in fascism but doesn't delve other reasons why e.g. tensions with increased number of migrants.
In my experience in visiting Italy for many years, I don't believe that fascism or racism are growing. I would comfortably say in my experience it has been the opposite. Italy certainly has an issue with racism, but I really don't see it in any way as bad or growing as the guy is suggesting. He also ignores any positive stories e.g. villages welcoming migrants or football teams set up to help migrants.
I'm not surprised the Guardian are jumping on this one, just like the did on the Ronaldo story.