There are a few big issues with trying to be funny on the internet. For one thing, it's almost impossible to get your tone across in text. It's way too easy for a sarcastic comment to be taken seriously and have the joke not only fall flat, but actually anger strangers.
For another, you really have to know your audience if you expect your jokes to land. I'm sure many would-be comedians had their careers cut short because their punchlines were delivered in the wrong room. And the internet has so very many wrong rooms.
And what even is comedy these days anyway? Is a troll job funny? Is it performance art? Is it just generally an annoying thing to do? It's hard to tell on the internet, isn't it?