The pope teaches infallibly regarding faith and morals when he invokes his charism of infalibility. This has only happened a handful of times, at most, in the past 150 years.
While that may be true, the public perception is that most Catholics believe the pope is “Infallible”.
If it is only in cases of faith and morals when invoking a special charism for that particular pronouncement, that is fine.
However, that is a very narrow definition and a fine distinction of which the average person is not aware. Most people, upon questioning, will not know about the special charism that has only been invoked a few times in the past 150 years, and are more likely to believe that the pope is infallible in matters of faith and morals without having to make a special invocation.
I did, after all, use the term “consider”. That means that, whatever the official stance is on this subject, the public perception is different. Abortion is definitely a matter of “Faith and Morals”, so whatever the pope says on the matter is going to affect Catholics, whether he invokes a charism or not.