The "dirty dozen" highlighted producing 65% of the content CCDH class as antivax have a combined 59 million social followers and are extremely prolific. So if nothing else, we can be sure that [by Facebook's metrics] there's a lot more than 18m obvious "pieces of misinformation" by any reasonable standard posted to Facebook over that timeline.
Of course it's not totally impossible Facebook's review process is so bad that they focused all their efforts on suppressing mainstream news stories about blood clots and people wondering whether they should still take it if they'd had adverse reactions to vaccines in the past. Certainly nobody would argue Facebook is perfect, but with the quantity of actual ludicrous antivax content out there clearly being greater than what they removed, it would have to be extraordinarily bad to have primarily targeted standard concerns. And that in itself would be worthy of discussion (and again CCDH specifically question whether Facebook's algorithms are adequate to distinguish between individual and organized vaccine hesitancy..)
You're responding to an article whose most dramatic claim is that a full two thirds of what they consider to be online COVID misinformation came from just 12 individuals. Extremely motivated individuals or not, that does tend to suggest the organization is letting a lot of more mainstream speculation slide.
Still the accounts are named, as are their backgrounds in peddling vitamin supplements and antivax literature and some examples of their posts about Bill Gates and microchips, medical industry plans to create chronically ill patients and the Pfizer vaccine killing more people than Covid. If you're going to call others "disingenuous" for "lumping these concerns in with the usual anti-vax crowd", perhaps you would like to tell us which one of the twelve accused individuals you believe is actually making reasoned arguments about testing procedures or possible evidence of side effects associated with some of these vaccines?