The ads shown are based on several factors including browsing history and the type of website you're on though Google doesn't disclose the precise criteria they use for choosing ads for a particular user. As far as Google is concerned, and these are Google Ads, this is a Catholic website and an ad for a movie about a "pope" is completely appropriate. Indeed, I get this movie ad sometimes as well but usually I don't even pay attention to or notice most Google ads.
Interestingly, at this moment, I looked at the ad at the bottom of the page and it is for a Protestant theological seminary. Why Google thinks this would be appropriate is beyond me.
But I do wonder...Does anyone ever click on Google ads? It seems about as dangerous (identify theft, etc.) as responding to someone who calls you trying to sell you insurance or a car warranty (which I get a couple of times a day) or that email from the Nigerian prince who wants to give you $25,000,000.
P.S. ETA: When I posted this the ad at the bottom of the page was for a seller of women's dresses. Since I recently purchased a dress for my daughter online, this is entirely understandable.