I think it's a broad generalization, and there are some jokes that only really work in image form (example 1 / example 2). Even the post I think you're referring to wouldn't really work without the image (except the random cat isn't really necessary).
If anything I'd say it's nice when the title text is setup to a joke, with the content (text or image) being the punchline. I personally try to come up with my own punchline before checking the description, so the format really works out. Agreed that the "rule" titles are low effort and belong in !196@lemmy.blahaj.zone but i just don't upvote those personally.