Based on the evidence in this case, it's just another newbie anti-Catholic poster; the source was immaterial as long as it smeared the Church, they'll buy into it. No need to look for themselves.
But, originally, who knows? You're right, comic books, Know Nothings... the usual 'reliable sources.'
The “disinformation” you all are espousing comes from your own church! From people who have come out and told what they were taught. I know, they are “poorly catechized, ignorant, not really Catholics, demented,” etc. Anything but truthful. When a person leaves a cult, they have much information to share about that cult. I don’t think they read comic books. I think they are really into the Bible. And what God ACTUALLY says. Not what they were told He says.