It has nothing to do with “infinite social responsibility”. It has to do with the fact that if someone supports a cause that consistently does evil, they share in responsibility for that evil. Voting for Nazis doesn’t get somebody off the hook just because they, personally don’t shove people into death camps.
And the “pro life” movement has always gone out of its way to cause death and suffering.
“Pro-life” is not about abortion. It was never about abortion. It is all about those nasty girls that get off on having sex – that is just all kinds of wrong.
For reference, the whole "pro-life* thing rose up right around the same time as the Equal Rights Amendment was being floated. Gotta get those uppity females put in their proper place. The way these people swing, next on their agenda is to make it child abuse to let your daughter be like a tomboy.