Do Italians really dislike tourists?

No — but there's real fatigue in the handful of places where tourism has swallowed daily life, particularly Venice, central Florence and parts of the Amalfi Coast. That frustration is about volume and behaviour, not about you personally. It disappears entirely two streets outside the tourist core, and in small towns you'll be met with straightforward warmth and curiosity. The things that genuinely irritate: treating a residential city as a theme park, blocking narrow streets, being loud in restaurants, and not greeting anyone. Behave like a guest in a place where people live and you'll have a completely different trip.