The claim that post birth abortion happens is a lie. That he believed it and repeated it means he had a wrong opinion.
Unless you are saying you know the man personally, and know for a fact he was lying about a claim he knew to be false.
A lie is something you know to be false and then you say it to deceive others. A wrong opinion is a belief in something that is false
For example, people who believed Joe Biden wasn't suffering from age related decline a few years ago had a wrong opinion ( By the way, that would include most people on this thread),
However, people in the Media (like Joe Scarborough) who claimed 3 or so months ago that he was as sharp as he had ever been or perhaps even the sharpest he'd ever seen him was lying.
Thee is a difference between the two.