This is a typical thing we have, people upset with someone defacing their things. What would people say if Catholics went around and did such things to people who disagreed with them (maybe anti-Catholic Protestant Churches)? Nobody would respect the Church, people would leave her. But, if you do something like that to the Church, people have no problem, and probably (at least secretly) support these detractors.
During the past week, graffiti have appeared on doors of Genoa's cathedral and other neighboring churches, with slogans such as "Bagnasco shame," and "Bagnasco beware." The graffiti-- which also includes insults to the Pope and to the Catholic faith generally-- appeared soon after the archbishop issued a public statement opposing the legal recognition of same-sex unions.
The spray-painted slogans are offensive in themselves, Avvenire argued. But they are even more objectionable because they inflame passions and promote intolerance against the Church. The slogans in themselves are indications of contempt, the editorial said, and the sentiments they convey "can move quickly from mouth to mouth and mind to mind," until they spur more violent reactions.
(Update: The vandalism has spread across Italy, confirming my point. Read more here.)