We adore You, O Christ, and we bless You, for by Your Holy Cross, You have redeemed the world.
Eveny Lent, during Stations of the Cross, we are reminded that the Lord Jesus redeemed the whole world. All of Creation has been redeemed and He is the Redeemer.
This does not mean that all of humanity will be saved, as if God takes us to Heaven against our own will. The Lord said clearly in the Holy Gospel that the road to eternal life is narrow and 'few be there that find it'.
If a person does good (objective good, rather than paying for an abortion), following conscience consistently, as others have said, he or she will find the One True Catholic Faith, in which the fullness of truth and goodness is communicated to us.
I do not believe the Holy Father has said something that is out of line with the Catholic tradition, but I would understand people saying it is open to a good interpretation or a bad one.
It sounds like the Holy Father is trying to open up a dialogue with atheists - a public 'Court of the Gentiles'. We can meet atheists in doing good and then, while doing good, bear witness to the Author of all that is good, but what we say when we meet them will, we pray, aid their eternal salvation and ours.
I cannot help but think how little Richard Dawkins speaks of the urgent need to 'do good'. All he seems to do is rubbish religious manifestations of 'good works'. I see in the Holy Father's words a rather clever way of approaching atheism, since 'doing good' seems not to be a big part of the atheistic agenda. The starting point of his homily seems to have been that 'doing good is a principle that unites all humanity'.
All this said, it is perhaps not surprising that the liberal press have leapt on the Holy Father's words.
The full homily is here.