That's a pretty pathetic offering (a copy of the Wikipedia article about Catalonia in Catalan). They could have at least tried to pick something the reader wouldn't already know about.
Yeah, I'm from catalonia and I'm ambivalent about this kind of usage. On the one hand, you have some meme sites that are cool, but are often just "exploiting" the tld to make for a nicer url. Aesthetics. As a hacker, it doesn't seem a problem at all... but then you have to consider the cultural issues too: catalonia is not that big, with 7.5M population. Should we consider the "inappropriate" use of .cat domains as a form of cultural appropriation? Might seem a bit exaggerated, but it's not a ridiculous question to ask oneself.
That being said, fundació.cat is allowing the sites to exist and doesn't seem to care that much either about what's going on in their domains (I sent them an email once asking for a list of all / the_most_popular .cat sites to find sites in catalonia worth promoting, and they don't even have that kind of information available), so if they don't care themselves, what can lowly citizens even ask for.
The objection isn't to using content from Wikipedia, the objection is that .cat websites are supposed to include Catalan content and this one chose to satisfy that requirement in the laziest and least interesting way possible. Why not pull from an article about something actually interesting and relevant to the site at least, rather than a couple intro paragraphs in Catalan about the place where most speakers of that language already live? It's not a huge deal but it seems like a missed opportunity.
Afaik, it's up to the country to determine the rules for the tld. Some require strict rules (eg, .us requires making public a current mailing address, something making me consider getting rid of mine as I don't want that so public), and others (eg, .io and .fm) simply use it as a way to make some money.
To be accurate it is not that you have to have content in Catalan (although that seems to be the _main_ purpose of the sponsored TLD) but you have to "be a part of the Catalan
Linguistic and Cultural Community" as set forth in the registry agreement between ICANN and domini.cat [0]