Let's be humble for a minute. As established, irony-poisoned citizens of internet humor, we enjoy thinking that nobody can get a sly punchline past us, but we're wrong. Everybody has their bad days, their blind spots, and the days that they're not thinking straight. It's inevitable that at some point, we have seen a joke online and completely misunderstood what it's trying to say.
That being said, there are some out there who are a lot more prone to this than others. Whether it's a lack of reading comprehension, or the fact that they are just plain dumb, people can frequently miss the point when they see their peers doing something funny on social media. It can be baffling, but it's not like we should complain: often, this just makes the whole thing funnier. There's a good reason that r/woooosh has been going for so long, and that's because it makes us feel smart and entertained.