I found information on Pope Leo here at New Advent newadvent.org/cathen/09154b.htm
I typed it into a general search engine and the first on the list was an Anti-Cathlic site.
I tried to find the source of the quote, and was unable to.
The truth is that yes, Christians used to have very public confessions. However, since Christ gave the Church the authority to make and change the rules, the procedure of confession being public to private was made. Catholic Christians still confess to God in front of “one another” ie a priest, but no longer are forced to stand and make a public confession to all.
And unless you belong to some very minor denominations, most Protestants do not require public confessions of sin. Most I went to never even required any confession at all except in your bedroom between you and God. And that definitely goes against confess your sins to one another.
p.s. I just went to CA. I may be wrong about confessions used to be public. But either way it doesn’t matter, they have always had to be done before a priest.
You may wish to spend some time in the CA tracts. They are short and easy to read and can answer many of your questions if you are seriously considering Catholicism.
or more generally here catholic.com/library.asp