Way back when I was in 2nd grade, we learned about mortal and venial sin.  The nun who taught us explained that although probably none of us had committed a mortal sin, we should remember that our soul was like a white piece of cloth, and sins were like black splotches on that cloth.  She said that a mortal sin would make the entire cloth black, but many smaller sins could do the same job.  
It would seem to me that some of those Trump-voting Catholics might have wanted to consider the fact that, while not labeled a "baby killer" (though no one will ever know if he paid for any abortions for girlfriends), perhaps his multitude of offenses might be just as bad as Hillary's alleged "support" of abortion.  Unfortunately, neither the hierarchy, nor the clergy, nor those voters seem capable of that kind of calculus.