It’s just bias.
Think, for example, of all the movies in the last twenty or thirty years that involved Catholicism. How many of them actually portrayed Catholicism realistically? Almost all of them just were set out to make it look like our leaders in red and black are evil, corrupt, power-hungry, blah, blah, blah. Is it true? Overall, no. Sure, there are some bad Bishops and probably some bad Cardinals, but that’s inevitable. Even the Aposles had Judas – and he was handpicked by Jesus. I mean, if all of Catholicism I saw was those movies, I’d probably hate Catholics too.
People will claim two things when you ask them. They will claim that, #1, they will not believe everything they hear and, #2, that they know movies and TV are not good sources to get a dose of reality. Yet they fail to pass the test. Think, for example, how many people believe that John Paul I was really killed because he wanted to reform a corrupt Curia? They see it on the Godfather and believe it’s true. They failed the test! You can understand why so many of us Catholics work hard to show people why the Da Vinci Code is rubbish – people say they aren’t easily suggested, but they are. It’s funny too, because if you watch documentaries on National Geographic or Discovery that do stuff on the Da Vinci Code, you’ll see how those historians tell us over and over again why the Da Vinci Code just has it wrong on so many issues.
So why do people like in your story hate us Catholics like that? For them, since they were taught so wrongly about Catholicism and since they see it reinforced by the media, the hate just grows.
The question naturally arises: why was it they were taught like this in the first place? Well, when the US was founded, it was almost completely by protestants, unitarians or deists. The only thing their faiths really had in common was hate for Catholicism. This hate gets passed down and still exists today in bias.
People of course will say that they aren’t biased against Catholicism at all. But, that’s what bias is: nobody admits having it.
Anyway, with all of that, at least you and I can thank God that you don’t have such stupid biases. You can tell it’s illogical.
People like the ones in your story will say so much against Catholicism, and when you ask for some proof, they will provide it. The thing is, though, a lot of the proof isn’t even real. They’ll say how Pius XII hated Jews and collaborated with Nazis (not true), they’ll say how the Pope has many titles that imply he thinks he’s Christ’s equal (also not true), and they’ll make countless other nonsensical claims, like saying that the Church just wants money and power (stop and think: how many greedy people would be willing to take a vow of poverty?).
It’s a lot like party politics. The political base in one party will believe whatever negative things they hear about the other party. I could give examples of the current election, but I don’t wanna go into candidates’ details like that since it’s against the rules here, but I think you get the point anyway. Cheerleaders will cheer their side even if their side is wrong.
Atheists say that religion has no logic or truth; in a funny way, it’s true, because when people complain about Catholicism, they don’t use logic or truth.