I don't want to say they bare zero responsibility for remaining ignorant and never seeking basic media literacy but: partly I really do think it's an inevitable consequence of both neoliberalism and the cult of celebrity. Art under neoliberalism is about commodifying and branding everything and I think most mainstream actors of today's generation are basically always playing two roles in any project. There's the role they have in the film, and the role they play on late night, press junkets, and social media that everyone in fandom sees. Most marvel stars are especially good examples of this one. People get thrown for a loop with a legend like de niro because he doesn't have to play that game and people aren't ready for it.