Or perhaps he believes that the corporation with evil is not proximal in this case? And to receive the vaccine is not sinful.
Just a guess, but I can envision that Benedict was not aware of the abortion tainted aspects. Do you really think those horrible people who surround him would explain? He's very very old, maybe still brilliant in many respects but nobody in their 90's is sharp an all. Very sad to see. This may be elder abuse.