I read that Pope Francis has said that many Catholics are sacramentalized but unevangelized. What does this mean? It seems to me that it denigrates the Sacraments.

I am unaware that Pope Francis has used this phrase. However, it is a rather common expression today among priests and theologians. It describes the unfortunately common reality of many Catholics in the pews who have received all their Sacraments, and may even faithfully attend Mass each Sunday and go to confession at least once a year, but they have never really met Jesus Christ or encountered his presence powerfully. 
 
Sadly, many Catholics, often due to poor catechesis, reduce the sacraments to rituals, rather than to living and real encounters with the Lord Jesus, who himself is the true celebrant of every Sacrament. The purpose of all the Sacraments is to sanctify us, and in particular ways, to lead us deeper and deeper into a life changing and transformative relationship with Jesus Christ. They are to put us in living, conscious contact with Jesus, so that we see our lives being changed. 
 
But the all-too-common experience of many Catholics is that Sacraments are only vaguely appreciated in this way. Many see them as tedious rituals, rather than transformative realities. Too many seek the shortest Mass almost as if it were more like a flu shot, a kind of “necessary evil,” to be dispensed with as quickly and painlessly as possible. Confession too is avoided. 
 
Very few Catholics come to Mass expecting to be transformed. In a way, people put more faith in Tylenol than the Eucharist since, when they take Tylenol, they expect something to happen, they expect the pain to go away and healing to be induced. But too many Catholics do NOT expect anything like this from the Holy Communion with Jesus. 
 
This is what is meant to be sacramentalized, but unevangelized. It is to be faithful to the pew and to the Sacraments but to lack the evangelical zeal, joy and transformation one would expect from a more fruitful reception of the Sacraments. It is to go through the motions but not really get anywhere. It is to receive Jesus but not really experience him in any meaningful manner. 
 
Pastors, parents and Catechists need to work to overcome what amounts to a lack of deep faith in, and experience of, Jesus. Far from denigrating the Sacraments, the phrase seeks to underscore the truer and fuller reality of the Sacraments, which are not mere rituals, but powerful realities if received fruitfully.