Because everyone knows where Catholic social teaching stands on Abortion. Everyone. What this Pope is doing in his Papacy as he outlined in an interview he did in 2013 is say that the Catholic Church needs a "new balance" in terms of the issues spoken off. 

Pro life doesn't just mean abortion. It includes issues like Capital Punishment, War, Economic Justice, etc. And this isn't just Francis or liberals pushing some far left agenda. Pope John Paul II has said some of the same things in his encyclical Evangelium Vitae.