If, on the other hand, one is “personally opposed,” but has no objections to others aborting, the implication must be that they actually don’t have any moral qualms about killing offspring. They are not interested themselves in having abortions, maybe because they want to have heirs, or they just enjoy kids, or they have a narcissistic yen to see concrete extensions of themselves. But if they had any moral objections, they should be willing to apply the principle in general. If it’s wrong for them, it’s wrong for others, too. Otherwise, they would be favoring a relativistic morality, in which it is impossible to say what is right or wrong. They could not even claim to be “personally against” because relativists are not consistently against any immoral practice. To paraphrase Kierkegaard: if it is sad to see persons hobbling around because of physical handicaps, it is even sadder to view people walking about without a conscience.
“...But if they had any moral objections, they should be willing to apply the principle in general. If it’s wrong for them, it’s wrong for others, too...”
Then we will end up with totalitarian society. Someone will decide for you how to live your life. History shows us again and again where we going to end up if individual liberties are not protected. Maybe you should care about thousands of children who killed every day around the world..