Generally, irony doesn't work with strangers because it's best to assume people mean what they say. No one expects irony from someone they don't know. (I actually got suspended once because something I said ironically was treated as unironic.)

Titles are particularly important because they should attract readers because they agree, or because they disagree, with the author's thesis. I came to this article because I wanted to read someone who disagreed with me. I've already written harshly about anti-vaxxers, and I wanted to see what defense might be offered against a not-ready-for-primetime shot. So, when I say I was "happy" not to have found an anti-vax essay, I meant that politically. In terms of time invested, I was disappointed to find that I was not going to get the contrary opinion I clicked to get.

On the flip side, people who might read your article if they agreed with you might skip it because they think from the title that you're a wacko anti-vaxxer.