It could be, sure, but it's often surprising what gaps other people have in their knowledge. There are lots of people whose knowledge of a given actor's or filmmaker's entire career is limited to one or two works and who've never had the curiosity to look further. For instance, a lot of people dismissed Robert Pattinson as Batman because they'd disliked him in Twilight and were totally unaware of the acclaimed work he'd done in indie films in the subsequent years. And there are plenty of people to whom Marlon Brando is just that weird guy who played Jor-El really stiffly. It's more common than you'd think for people to know a person only from the roles they've seen and have zero curiosity about finding out what else they've done.
So I can totally buy that there's somebody out there who knows Tim Burton as the guy who did, say, Charlie and the Chocolate Factory and Sweeney Todd and Dark Shadows, or maybe is even aware that he did earlier Johnny Depp vehicles like Edward Scissorhands and Sleepy Hollow, but has never bothered to investigate what else Burton has done. I mean, from his later filmography, it would never occur to anyone to suspect he'd ever made a superhero movie; the modern perception of what superhero movies are like just doesn't align with the perception of what Tim Burton movies are like. And he's become so associated with Depp over the years that I don't doubt there are people who stereotype him as "the guy who makes weird Johnny Depp movies" and nothing more. After all, the tweet in question featured a screencap of Pattinson looking particularly Depp-ish, with emo hair and dark eye shadow.