Jokes within thoughtful comments have no problem to get upvoted here. Don't mistake "apparent humorless" for "completely dry", as many highly upvoted comments do contain humor, but it's more subtle and within a comment that is insightful even without the joke, not just a comment containing a joke without anything else.

On Reddit there is a lot of jokes, but most of them are replicas or just pure memes that gets repeated ad infinitum, nothing that really cracks me up except some rare ones. But on HN, when there is a highly upvoted comment with a joke somewhere within, it's always good one that contributes to the comments otherwise insightful points.

The problem is not humor on online forums being "low effort", it's "low SNR".

The problem is when everyone thinks that they have some unique insight and that their cynical one-liners are worthy to be written down. Put that together with the development of "in-groups", and you'd see most of the threads becoming sequences of re-hashed jokes. You get "ha-ha funny" posts, but you get no one really challenging anything related to the topic and you drown out those that might actually have something to add to the conversation.

Good comedy/satire works when it manages to bring new insight into a topic. If you have such talent and your comment can be insightful and humorous, I doubt you'd have trouble with the crowd.