Earlier quoted context omitted.
I'm speculating based on the rules in Finland, assuming they would be quite similar in Italy. In Finland a store may not choose their customers based on a broad criteria (such as age, ethnicity, disability, sexual orientation or other reason related to the person). I'm sure being poor would be included in this list. Badly behaving customers can be expelled.
I see. There is no such rule in the U.S., although a lot of people mistakenly assume there is one. So I thought you might just be mistaken. I'm not sure whether the law in Italy is more similar to the U.S., or to Finland.
Careful with online lawyering, its illegal not to bake a marriage cake for a gay couple, to cite a recent famous example.